diff --git a/.appveyor.yml b/.appveyor.yml
index d4253db82..8c3334fde 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -27,7 +27,8 @@ install:
   # also install shells and script interpreter for test purpose
   # no availability of R on MSYS2 platform
   - if "%BUILD_PLATFORM%" == "msys" (%CMD_DIR%\bash -lc "pacman --noconfirm --noprogressbar -S tcl dejagnu python ruby cmake zsh tcsh mksh fish gcc autoconf")
-  - if "%BUILD_PLATFORM%" == "cygwin" (%CMD_DIR%\bash -lc "/setup-x86_64.exe -qnNdO -P tcl,dejagnu,ruby,cmake,zsh,tcsh,mksh,fish,R,tcl-devel,gcc-core,autoconf")
+  # temporarily stop to test against CMake on Cygwin platform (see https://github.com/appveyor/ci/issues/3508)
+  - if "%BUILD_PLATFORM%" == "cygwin" (%CMD_DIR%\bash -lc "/setup-x86_64.exe -qnNdO -P tcl,dejagnu,ruby,zsh,tcsh,mksh,fish,R,tcl-devel,gcc-core,autoconf")
   # install Tcl for native test and requirement in Cygwin to build Windows-specific dist zipball
   - if "%BUILD_PLATFORM%" == "native" (%CMD_DIR%\bash -lc "/setup-x86_64.exe -qnNdO -P tcl,python37,python37-sphinx,zip")
   - if "%BUILD_PLATFORM%" == "native" (
diff --git a/.travis.yml b/.travis.yml
index 3fb790ab4..032fddfba 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -142,7 +142,7 @@ jobs:
             # compatibility version-specific build requirements
             - automake
             - autopoint
-    - env: CONFIGURE_OPTS='--with-tclsh=tclsh8.6 --prefix=/tmp/modules --enable-compat-version --with-tcl=/usr/lib/tcl8.6 --enable-append-manpath --enable-append-binpath --with-bin-search-path=/usr/bin:/bin --disable-silent-shell-debug-support --enable-windows-support --with-loadedmodules=null:dot --with-quarantine-vars=LD_LIBRARY_PATH --enable-color --with-dark-background-colors=hi=1:se=2:er=91:wa=93:mp=1;94:di=94:al=96:sy=95'
+    - env: CONFIGURE_OPTS='--with-tclsh=tclsh8.6 --prefix /tmp/modules --enable-compat-version --with-tcl=/usr/lib/tcl8.6 --enable-append-manpath --enable-append-binpath --with-bin-search-path=/usr/bin:/bin --disable-silent-shell-debug-support --enable-windows-support --with-loadedmodules=null:dot --with-quarantine-vars=LD_LIBRARY_PATH --enable-color --with-dark-background-colors=hi=1:se=2:er=91:wa=93:mp=1;94:di=94:al=96:sy=95 --enable-foo FOO=bar'
            EXTRA_SCRIPT_CD='modules-1.2.3+branch_name-91-g6dd3db49'
       addons:
         apt:
@@ -245,7 +245,7 @@ jobs:
     # also enable a display on this test case to validate x-resource behavior
     - env: OS_NAME=centos OS_VERSION=6 DOCKER_IMAGE=${OS_NAME}:${OS_NAME}${OS_VERSION} CONTAINER=${OS_NAME}${OS_VERSION}
            CMD_PREFIX="docker exec --env RUNTESTFLAGS=-v $CONTAINER xvfb-run"
-           CONFIGURE_OPTS='--prefix=/tmp/modules --enable-compat-version --with-loadedmodules=null:dot --with-quarantine-vars=LD_LIBRARY_PATH LD_PRELOAD'
+           CONFIGURE_OPTS='--prefix /tmp/modules --enable-compat-version --with-loadedmodules=null:dot' CONFIGURE_OPTS_EXTRA='--with-quarantine-vars=LD_LIBRARY_PATH LD_PRELOAD'
            EXTRA_PKGS='xorg-x11-server-utils xorg-x11-server-Xvfb automake gettext-devel libX11-devel tclx-devel'
            EXTRA_SCRIPT_POSTINST='make srpm rpm'
       services:
@@ -253,7 +253,7 @@ jobs:
 
     - env: OS_NAME=centos OS_VERSION=7 DOCKER_IMAGE=${OS_NAME}:${OS_NAME}${OS_VERSION} CONTAINER=${OS_NAME}${OS_VERSION}
            CMD_PREFIX="docker exec --env RUNTESTFLAGS=-v $CONTAINER xvfb-run"
-           CONFIGURE_OPTS='--prefix=/tmp/modules --enable-compat-version --with-loadedmodules=null:dot --with-quarantine-vars=LD_LIBRARY_PATH LD_PRELOAD'
+           CONFIGURE_OPTS='--prefix=/tmp/modules --enable-compat-version --with-loadedmodules=null:dot' CONFIGURE_OPTS_EXTRA='--with-quarantine-vars=LD_LIBRARY_PATH LD_PRELOAD'
            EXTRA_PKGS='which xorg-x11-server-utils xorg-x11-server-Xvfb automake gettext-devel libX11-devel tclx-devel'
            EXTRA_SCRIPT_POSTINST='make srpm rpm'
       services:
@@ -261,7 +261,7 @@ jobs:
 
     - env: OS_NAME=centos OS_VERSION=8 DOCKER_IMAGE=${OS_NAME}:${OS_NAME}${OS_VERSION} CONTAINER=${OS_NAME}${OS_VERSION}
            CMD_PREFIX="docker exec --env RUNTESTFLAGS=-v $CONTAINER xvfb-run"
-           CONFIGURE_OPTS='--prefix=/tmp/modules --enable-compat-version --with-loadedmodules=null:dot --with-quarantine-vars=LD_LIBRARY_PATH LD_PRELOAD'
+           CONFIGURE_OPTS='--prefix=/tmp/modules --enable-compat-version --with-loadedmodules=null:dot' CONFIGURE_OPTS_EXTRA='--with-quarantine-vars=LD_LIBRARY_PATH LD_PRELOAD'
            EXTRA_PKGS='which xorg-x11-server-utils xorg-x11-server-Xvfb automake gettext-devel libX11-devel'
            EXTRA_SCRIPT_POSTINST='make srpm rpm'
       services:
@@ -277,7 +277,7 @@ jobs:
     # also enable a display on this test case to validate x-resource behavior
     - env: OS_NAME=opensuse OS_VERSION=leap DOCKER_IMAGE=${OS_NAME}/${OS_VERSION} CONTAINER=${OS_VERSION}
            CMD_PREFIX="docker exec --env RUNTESTFLAGS=-v $CONTAINER xvfb-run"
-           CONFIGURE_OPTS='--prefix=/tmp/modules --enable-compat-version --enable-versioning --with-loadedmodules=null:dot --with-quarantine-vars=LD_LIBRARY_PATH LD_PRELOAD'
+           CONFIGURE_OPTS='--prefix=/tmp/modules --enable-compat-version --enable-versioning --with-loadedmodules=null:dot' CONFIGURE_OPTS_EXTRA='--with-quarantine-vars=LD_LIBRARY_PATH LD_PRELOAD'
            EXTRA_PKGS='which xrdb xvfb-run automake gettext-tools'
       services:
         - docker
@@ -335,7 +335,8 @@ before_script: |
   fi
 
 script:
-  - $CMD_PREFIX ./configure $CONFIGURE_OPTS
+  - if [ -z "$CONFIGURE_OPTS_EXTRA" ]; then $CMD_PREFIX ./configure $CONFIGURE_OPTS; fi
+  - if [ -n "$CONFIGURE_OPTS_EXTRA" ]; then $CMD_PREFIX ./configure $CONFIGURE_OPTS "$CONFIGURE_OPTS_EXTRA"; fi
   - $CMD_PREFIX make
   - if [ -n "$EXTRA_SCRIPT_PRETEST" ]; then $CMD_PREFIX eval $EXTRA_SCRIPT_PRETEST; fi
   - travis_retry $CMD_PREFIX make test-deps
diff --git a/NEWS.rst b/NEWS.rst
index 2da8453ad..29e753776 100644
--- a/NEWS.rst
+++ b/NEWS.rst
@@ -6,6 +6,67 @@ Release notes
 This file describes changes in recent versions of Modules. It primarily
 documents those changes that are of interest to users and admins.
 
+Modules 4.5.3 (2020-08-31)
+--------------------------
+
+* Install: take into account the ``--build``, ``--host``, ``--target``,
+  ``--enable-dependency-tracking`` and ``--disable-dependency-tracking``
+  configure options to transmit them to the :file:`configure` scripts of
+  Modules Tcl extension library and Modules compatibility version. (fix issue
+  #354)
+* Install: ignore some regular options of an Autoconf :file:`configure` script
+  that are useless for this project but usually implied in build macros (like
+  RPM ``%configure`` macro).
+* Install: ignore unsupported ``--enable-*`` and ``--with-*`` options on
+  :file:`configure` script rather raise an error and add support to define
+  environment variable and build system type as :file:`configure` script
+  arguments to comply with `GNU configuration recommendations`_.
+* Install: fix :file:`modulecmd` pre-alternatives check in RPM spec file.
+* Install: use ``%make_build`` and ``%make_install`` macros in RPM spec file.
+* When :mfcmd:`module switch<module>` command is used in modulefile, do not
+  state when processing it a conflict over switched-off module if its
+  specification on the ``module switch`` command also matches switched-on
+  module's specification. Allow this way the replacement of any loaded version
+  of a module for a specific one required by currently loading module. (fix
+  issue #355)
+* Correctly report failed attempts to load module requirements expressed with
+  advanced version specifiers. (fix issue #356)
+
+.. _GNU configuration recommendations: https://www.gnu.org/prep/standards/html_node/Configuration.html
+
+
+Modules 4.5.2 (2020-07-30)
+--------------------------
+
+* Init: :subcmd:`list` and :subcmd:`source` sub-commands do not take available
+  modules as argument in fish completion script.
+* Init: fix option list for :subcmd:`search` sub-command in bash completion
+  script.
+* Fix double error counter increase when modulefile evaluation breaks.
+* Install: adapt :file:`configure` script to pass to the :file:`configure`
+  script of Modules compatibility version only a subset of the options it
+  supports (most commonly used options).
+* Install: raise an error when an unknown option is passed to
+  :file:`configure` script rather silently ignore it. (fix issue #348)
+* Install: enable the definition of installation directory options of
+  :file:`configure` script with the ``--option value`` syntax in addition to
+  the ``--option=value`` syntax. (fix issue #348)
+* Doc: alphabetically sort sub-commands of :mfcmd:`module-info` modulefile Tcl
+  command in :ref:`modulefile(4)` document.
+* Script: clean previously built environment-modules RPMs in :command:`mrel`.
+* Clearly separate quarantine variable definition from tclsh binary on
+  :file:`modulecmd.tcl` evaluated command call in ``_module_raw`` function for
+  *sh*, *bash*, *ksh* and *zsh* shells. (fix issue #350)
+* Doc: clarify in documentation index that Environment Modules should not be
+  confused with language-specific modules. (contribution from Rob Hurt)
+* Adapt conflict detection tests to ensure a module loaded by its full
+  pathname will not detect itself as a conflict when declaring a reflexive
+  conflict. (fix issue #352)
+* Adapt the :command:`mrel` and :command:`mpub` commands to produce new
+  Modules release from a *vZ.Y.x* git branch rather than from the repository
+  main branch.
+
+
 Modules 4.5.1 (2020-06-01)
 --------------------------
 
diff --git a/configure b/configure
index 3407706ea..4f5b90788 100755
--- a/configure
+++ b/configure
@@ -120,7 +120,12 @@ compatbranch='c-3.2'
 
 # print message on stderr then exit
 echo_error() {
-   echo -e "ERROR: $1" >&2
+   if [ $# -eq 2 ] && [ $2 -eq 1 ]; then
+      local tryhelp="\n  Try \`$progpath --help' for more information"
+   else
+      local tryhelp=''
+   fi
+   echo -e "ERROR: $1$tryhelp" >&2
    exit 1
 }
 
@@ -399,29 +404,68 @@ get_package_value() {
 
 # parse arguments
 for arg in "$@"; do
+   # set argument value defined with "--arg val" form
+   if [ -n "${nextargisval+x}" ]; then
+      declare $nextargisval=$arg
+      unset nextargisval
+      continue
+   # set compat and lib argument value defined with "--arg val" form
+   elif [ -n "${nextargiscompatlibarg+x}" ]; then
+      compatarglist+="$arg "
+      libarglist+="$arg " ;
+      unset nextargiscompatlibarg
+      continue
+   # current arg should be skipped
+   elif [ -n "${nextargisign+x}" ]; then
+      unset nextargisign
+      continue
+   fi
+
    case "$arg" in
    --prefix=*)
       prefix="${arg#*=}" ;;
+   --prefix)
+      nextargisval=prefix ;;
    --bindir=*)
       bindir="${arg#*=}" ;;
+   --bindir)
+      nextargisval=bindir ;;
    --libdir=*)
       libdir="${arg#*=}" ;;
+   --libdir)
+      nextargisval=libdir ;;
    --libexecdir=*)
       libexecdir="${arg#*=}" ;;
+   --libexecdir)
+      nextargisval=libexecdir ;;
    --etcdir=*)
       etcdir="${arg#*=}" ;;
+   --etcdir)
+      nextargisval=etcdir ;;
    --initdir=*)
       initdir="${arg#*=}" ;;
+   --initdir)
+      nextargisval=initdir ;;
    --datarootdir=*)
       datarootdir="${arg#*=}" ;;
+   --datarootdir)
+      nextargisval=datarootdir ;;
    --mandir=*)
       mandir="${arg#*=}" ;;
+   --mandir)
+      nextargisval=mandir ;;
    --docdir=*)
       docdir="${arg#*=}" ;;
+   --docdir)
+      nextargisval=docdir ;;
    --vimdatadir=*)
       vimdatadir="${arg#*=}" ;;
+   --vimdatadir)
+      nextargisval=vimdatadir ;;
    --modulefilesdir=*)
       modulefilesdir="${arg#*=}" ;;
+   --modulefilesdir)
+      nextargisval=modulefilesdir ;;
    --enable-set-manpath*|--disable-set-manpath)
       setmanpath=$(get_feature_value "$arg") ;;
    --enable-append-manpath*|--disable-append-manpath)
@@ -558,8 +602,54 @@ for arg in "$@"; do
       echo_usage
       exit 0
       ;;
-   *)
+   --build|--host|--target)
+      # pass argument supported by compat version anb lib to their ./configure
+      # script
+      compatarglist+="$arg " ;
+      libarglist+="$arg " ;
+      # and set next arg should also be send to compat version and lib scripts
+      nextargiscompatlibarg=y ;;
+   --build=*|--host=*|--target=*)
+      # pass argument supported by compat version anb lib to their ./configure
+      # script
+      compatarglist+="$arg " ;
+      libarglist+="$arg " ;;
+   --with-tcl-lib=*|--without-tcl-lib|--with-tcl-ver=*|--without-tcl-ver|\
+   --with-tclx=*|--without-tclx|--with-tclx-ver=*|--without-tclx-ver|\
+   --with-tclx-lib=*|--without-tclx-lib|--with-tclx-inc=*|--without-tclx-inc|\
+   --with-x|--without-x|--enable-dependency-tracking*|\
+   --disable-dependency-tracking)
+      # pass argument supported by compat version to its ./configure script
       compatarglist+="$arg " ;;
+   --program-prefix|--program-suffix|--program-transform-name|--exec-prefix|\
+   --sbindir|--sysconfdir|--datadir|--includedir|--localstatedir|\
+   --sharedstatedir|--infodir|--runstatedir|--oldincludedir|--localedir|\
+   --htmldir|--dvidir|--pdfdir|--psdir)
+      # ignore standard configure option and value which has no meaning here
+      echo_warning "Option \`$arg' ignored" ;
+      nextargisign=y ;;
+   --program-prefix=*|--program-suffix=*|--program-transform-name=*|\
+   --exec-prefix=*|--sbindir=*|--sysconfdir=*|--datadir=*|--includedir=*|\
+   --localstatedir=*|--sharedstatedir=*|--infodir=*|--runstatedir=*|\
+   --oldincludedir=*|--localedir=*|--htmldir=*|--dvidir=*|--pdfdir=*|\
+   --psdir=*)
+      # ignore standard configure option which has no meaning here
+      echo_warning "Option \`$arg' ignored" ;;
+   --enable-*|--disable-*|--with-*|--without-*)
+      # ignore --enable-*/--with-* options not supported here to comply with
+      # GNU Configuration specification
+      # (https://www.gnu.org/prep/standards/html_node/Configuration.html)
+      echo_warning "Option \`$arg' ignored" ;;
+   -*)
+      echo_error "Unrecognized option \`$arg'" 1;;
+   *=*)
+      echo -e "Export \`$arg' in environment" ;
+      export $arg ;;
+   *)
+      # type of system to build the program for (not needed here but useful
+      # for true autoconf configure scripts below
+      compatarglist+="$arg " ;
+      libarglist+="$arg " ;;
    esac
 done
 
@@ -846,6 +936,7 @@ done
 # configure extension library sources
 if [ "$libtclenvmodules" = 'y' ]; then
    echo "--- configuring extension library sources --------"
+   echo "libarglist = $libarglist"
    pushd lib
    ./configure $libarglist || exit 1
    popd
@@ -855,6 +946,7 @@ fi
 # configure compat version sources
 if [ "$compatversion" = 'y' ]; then
    echo "--- configuring compatibility version sources ----"
+   echo "compatarglist = $compatarglist"
    pushd compat
    # unknown arguments for this configure script are passed down to the
    # compatibility version configure script (which raise error if arg unknown)
diff --git a/contrib/rpm/environment-modules.spec.in b/contrib/rpm/environment-modules.spec.in
index 652957602..caae421d7 100644
--- a/contrib/rpm/environment-modules.spec.in
+++ b/contrib/rpm/environment-modules.spec.in
@@ -2,7 +2,7 @@
 %global vimdatadir %{_datadir}/vim/vimfiles
 
 Name:           environment-modules
-Version:        4.5.1
+Version:        4.5.3
 Release:        @MODULES_RPM_RELEASE@%{?dist}
 Summary:        Provides dynamic modification of a user's environment
 
@@ -105,8 +105,10 @@ This package provides Environment Modules compatibility version (3.2).
 %endif
 
 # configure script for this software is not generated by autoconf
-./configure --prefix=%{_datadir}/Modules \
+%configure --prefix=%{_datadir}/Modules \
+            --bindir=%{_datadir}/Modules/bin \
             --libdir=%{_libdir} \
+            --libexecdir=%{_datadir}/Modules/libexec \
             --etcdir=%{_sysconfdir}/%{name} \
             --mandir=%{_mandir} \
             --vimdatadir=%{vimdatadir} \
@@ -117,11 +119,20 @@ This package provides Environment Modules compatibility version (3.2).
             --with-initconf-in=etcdir \
             --with-modulepath=%{_datadir}/Modules/modulefiles:%{_sysconfdir}/modulefiles:%{_datadir}/modulefiles \
             --with-quarantine-vars='LD_LIBRARY_PATH LD_PRELOAD'
-make %{?_smp_mflags}
+
+%if 0%{?fedora} >= 22 || 0%{?rhel} >= 7
+    %make_build
+%else
+    make %{?_smp_mflags}
+%endif
 
 
 %install
-make install DESTDIR=%{buildroot}
+%if 0%{?fedora} >= 22 || 0%{?rhel} >= 7
+    %make_install
+%else
+    make install DESTDIR=%{buildroot}
+%endif
 
 mkdir -p %{buildroot}%{_sysconfdir}/modulefiles
 mkdir -p %{buildroot}%{_datadir}/modulefiles
@@ -164,7 +175,7 @@ make test
 # Cleanup from pre-alternatives
 [ ! -L %{_sysconfdir}/profile.d/modules.sh ] &&  rm -f %{_sysconfdir}/profile.d/modules.sh
 [ ! -L %{_sysconfdir}/profile.d/modules.csh ] &&  rm -f %{_sysconfdir}/profile.d/modules.csh
-[ ! -L %{buildroot}%{_bindir}/modulecmd ] &&  rm -f %{_bindir}/modulecmd
+[ ! -L %{_bindir}/modulecmd ] &&  rm -f %{_bindir}/modulecmd
 
 # Migration from version 3.x to 4
 if [ "$(readlink /etc/alternatives/modules.sh)" = '%{_datadir}/Modules/init/modules.sh' ]; then
@@ -241,6 +252,15 @@ fi
 
 
 %changelog
+* Mon Aug 31 2020 Xavier Delaruelle <xavier.delaruelle@cea.fr> - 4.5.3-1
+- Update to 4.5.3
+- Use 'configure' macro
+- Fix modulecmd pre-alternatives cleanup check
+- Use 'make_build' and 'make_install' macros
+
+* Thu Jul 30 2020 Xavier Delaruelle <xavier.delaruelle@cea.fr> - 4.5.2-1
+- Update to 4.5.2
+
 * Mon Jun 01 2020 Xavier Delaruelle <xavier.delaruelle@cea.fr> - 4.5.1-1
 - Update to 4.5.1
 
diff --git a/doc/source/index.rst b/doc/source/index.rst
index fbad3ab10..8f82b9b6c 100644
--- a/doc/source/index.rst
+++ b/doc/source/index.rst
@@ -7,14 +7,14 @@ Environment Modules
 Modules package provides for the dynamic modification of a user's environment
 via modulefiles.**
 
-The Modules package is a tool that simplify shell initialization and
-lets users easily modify their environment during the session with
+The Modules package is a tool that simplifies shell initialization and
+lets users easily modify their environment during a session using
 modulefiles.
 
 Each modulefile contains the information needed to configure the shell for
 an application. Once the Modules package is initialized, the environment
-can be modified on a per-module basis using the module command which
-interprets modulefiles. Typically modulefiles instruct the module command
+can be modified on a per-module basis using the `module` command which
+interprets modulefiles. Typically modulefiles instruct the `module` command
 to alter or set shell environment variables such as ``PATH``, ``MANPATH``,
 etc. modulefiles may be shared by many users on a system and users may
 have their own collection to supplement or replace the shared modulefiles.
@@ -28,6 +28,10 @@ Modules are useful in managing different versions of applications. Modules
 can also be bundled into metamodules that will load an entire suite of
 different applications.
 
+.. note:: Modules presented here are ones that modify the shell or script
+   execution environment. They should not be confused with language-specific
+   modules (e.g., Perl modules, Python modules or R modules) that add specific
+   capabilities to scripts.
 
 Quick examples
 --------------
diff --git a/doc/source/modulefile.rst b/doc/source/modulefile.rst
index 48901b38b..a1245319e 100644
--- a/doc/source/modulefile.rst
+++ b/doc/source/modulefile.rst
@@ -247,20 +247,10 @@ the *modulefile* is being loaded.
  *option* is the type of information to be provided, and *info-args* are any
  arguments needed.
 
- **module-info type**
-
-  Returns either ``C`` or ``Tcl`` to indicate which :command:`module` command
-  is being  executed, either the C version or the Tcl-only version, to allow
-  the *modulefile* writer to handle any differences between the two.
-
- **module-info mode** [modetype]
-
-  Returns the current :file:`modulecmd.tcl`'s mode as a string if no
-  *modetype* is given.
+ **module-info alias** name
 
-  Returns ``1`` if :file:`modulecmd.tcl`'s mode is *modetype*. *modetype* can
-  be: ``load``, ``unload``, ``remove``, ``switch``, ``display``, ``help``,
-  ``test`` or ``whatis``.
+  Returns the full *modulefile* name to which the *modulefile* alias *name*
+  is assigned
 
  **module-info command** [commandname]
 
@@ -276,16 +266,33 @@ the *modulefile* is being loaded.
 
      .. versionadded:: 4.0
 
+ **module-info loaded** modulefile
+
+  Returns the names of currently loaded modules matching passed *modulefile*.
+  The parameter *modulefile* might either be a fully qualified *modulefile*
+  with name and version or just a directory which in case all loaded
+  *modulefiles* from the directory will be returned. The parameter
+  *modulefile* may also be a symbolic modulefile name or a modulefile alias.
+
+  .. only:: html
+
+     .. versionadded:: 4.1
+
+ **module-info mode** [modetype]
+
+  Returns the current :file:`modulecmd.tcl`'s mode as a string if no
+  *modetype* is given.
+
+  Returns ``1`` if :file:`modulecmd.tcl`'s mode is *modetype*. *modetype* can
+  be: ``load``, ``unload``, ``remove``, ``switch``, ``display``, ``help``,
+  ``test`` or ``whatis``.
+
  **module-info name**
 
   Return the name of the *modulefile*. This is not the full pathname for
   *modulefile*. See the `Modules Variables`_ section for information on the
   full pathname.
 
- **module-info specified**
-
-  Return the name of the *modulefile* specified on the command line.
-
  **module-info shell** [shellname]
 
   Return the current shell under which :file:`modulecmd.tcl` was invoked if
@@ -311,17 +318,9 @@ the *modulefile* is being loaded.
   *shelltypename* can be: ``sh``, ``csh``, ``fish``, ``tcl``, ``perl``,
   ``python``, ``ruby``, ``lisp``, ``cmake``, ``r``.
 
- **module-info alias** name
-
-  Returns the full *modulefile* name to which the *modulefile* alias *name*
-  is assigned
-
- **module-info version** modulefile
+ **module-info specified**
 
-  Returns the physical module name and version of the passed symbolic
-  version *modulefile*.  The parameter *modulefile* might either be a full
-  qualified *modulefile* with name and version, another symbolic *modulefile*
-  name or a *modulefile* alias.
+  Return the name of the *modulefile* specified on the command line.
 
  **module-info symbols** modulefile
 
@@ -330,17 +329,18 @@ the *modulefile* is being loaded.
   *modulefile* with name and version, another symbolic *modulefile* name
   or a *modulefile* alias.
 
- **module-info loaded** modulefile
+ **module-info type**
 
-  Returns the names of currently loaded modules matching passed *modulefile*.
-  The parameter *modulefile* might either be a fully qualified *modulefile*
-  with name and version or just a directory which in case all loaded
-  *modulefiles* from the directory will be returned. The parameter
-  *modulefile* may also be a symbolic modulefile name or a modulefile alias.
+  Returns either ``C`` or ``Tcl`` to indicate which :command:`module` command
+  is being  executed, either the C version or the Tcl-only version, to allow
+  the *modulefile* writer to handle any differences between the two.
 
-  .. only:: html
+ **module-info version** modulefile
 
-     .. versionadded:: 4.1
+  Returns the physical module name and version of the passed symbolic
+  version *modulefile*.  The parameter *modulefile* might either be a full
+  qualified *modulefile* with name and version, another symbolic *modulefile*
+  name or a *modulefile* alias.
 
 .. mfcmd:: module-version modulefile version-name...
 
diff --git a/init/bash_completion.in b/init/bash_completion.in
index bb171a4df..f898be98c 100644
--- a/init/bash_completion.in
+++ b/init/bash_completion.in
@@ -151,7 +151,7 @@ _module() {
     apropos|keyword|search)
                     COMPREPLY=( $(compgen -W "$search_opts" -- "$cur") );;
     config|--reset) COMPREPLY=( $(compgen -W "$config_opts" -- "$cur") );;
-    -h|--help|-V|--version|aliases|apropos|keyword|purge|refresh|reload|search|source)
+    -h|--help|-V|--version|aliases|purge|refresh|reload|source)
                     ;;
     append-path|prepend-path)
                     COMPREPLY=( $(compgen -W "$path_opts" -- "$cur") );;
@@ -226,7 +226,7 @@ if $(type -t ml >/dev/null); then
         apropos|keyword|search)
                         COMPREPLY=( $(compgen -W "$search_opts" -- "$cur") );;
         config|--reset) COMPREPLY=( $(compgen -W "$config_opts" -- "$cur") );;
-        -h|--help|-V|--version|aliases|apropos|keyword|purge|refresh|reload|search|source)
+        -h|--help|-V|--version|aliases|purge|refresh|reload|source)
                         ;;
         append-path|prepend-path)
                         COMPREPLY=( $(compgen -W "$path_opts" -- "$cur") );;
diff --git a/init/fish_completion b/init/fish_completion
index f75409e00..c603a713e 100644
--- a/init/fish_completion
+++ b/init/fish_completion
@@ -11,7 +11,7 @@ end
 
 function __fish_module_use_avail --description 'Test if module command should have available packages as potential completion'
    for i in (commandline -opc)
-      if contains -- $i help add load swap switch show display list avail is-loaded is-avail info-loaded source whatis test initadd initprepend path paths
+      if contains -- $i help add load swap switch show display avail is-loaded is-avail info-loaded whatis test initadd initprepend path paths
          return 0
       end
    end
diff --git a/modulecmd.tcl.in b/modulecmd.tcl.in
index 6d3c45632..d728cf0e7 100644
--- a/modulecmd.tcl.in
+++ b/modulecmd.tcl.in
@@ -1391,12 +1391,13 @@ proc execute-modulefile {modfile modname modspec {must_have_cookie 1}} {
          } elseif {$errorMsg eq {invoked "break" outside of a loop}\
             || ($errorMsg eq {} && (![info exists ::errorInfo]\
             || $::errorInfo eq {}))} {
-            raiseErrorCount
             unset errorMsg
             # report load/unload evaluation break if verbosity level >= normal
             if {([module-info mode load] || [module-info mode unload]) &&\
                [isVerbosityLevel normal]} {
                reportError {Module evaluation aborted}
+            } else {
+               raiseErrorCount
             }
             return 1
          } elseif {$errorCode eq {MODULES_ERR_SUBFAILED}} {
@@ -3226,6 +3227,10 @@ proc is-loading {args} {
 proc conflict {args} {
    reportDebug $args
    set currentModule [currentModuleName]
+   # get module short name if loaded by its full pathname
+   if {[set isfullpath [isModuleFullPath $currentModule]]} {
+      set currentSModule [findModuleNameFromModulefile $currentModule]
+   }
    defineModEqProc [isIcase] [getConf extended_default]
 
    # parse module version specification
@@ -3238,6 +3243,7 @@ proc conflict {args} {
       # if the conflict module is loading and it does not correspond to
       # currently evaluated module, we cannot proceed
       set isloading [expr {![doesModuleMatchesName $currentModule $mod] &&\
+         (!$isfullpath || ![doesModuleMatchesName $currentSModule $mod]) &&\
          [is-loading $mod]}]
       # if the conflicting module is loaded, we cannot either
       if {[is-loaded $mod] || $isloading} {
@@ -3734,9 +3740,11 @@ proc isModuleEvaluated {context exclmod args} {
    foreach evalmod [lsearch -all -inline -not [array names\
       ::g_moduleEvalAttempt] $exclmod] {
       set evalmatch 0
-      # test arguments against all names of evaluated module
-      foreach mod [concat [list $evalmod] [getAllModuleResolvedName\
-         $evalmod]] {
+      # test arguments against all names of evaluated module (translate
+      # eventual modspec in evalmod into module names, in case module
+      # evaluation stopped prior module name setup)
+      foreach mod [concat [getAllModulesFromVersSpec $evalmod]\
+         [getAllModuleResolvedName $evalmod]] {
          foreach name $args {
             if {[modEq $name $mod eqstart]} {
                set evalmatch 1
@@ -4553,16 +4561,21 @@ proc doesModuleConflict {mod} {
    set modconlist {}
    set moddecconlist {}
    defineModEqProc [isIcase] [getConf extended_default]
+   # get module short name if loaded by its full pathname
+   if {[set isfullpath [isModuleFullPath $mod]]} {
+      set smod [findModuleNameFromModulefile $mod]
+   }
 
    # check if any loaded module has declared a conflict
    foreach modcon [array names ::g_loadedModuleConflict] {
       # look if some loaded or loading modules correspond to conflict defined
       # by mod
-      if {$modcon eq $mod} {
+      if {$modcon eq $mod || ($isfullpath && $modcon eq $smod)} {
          foreach withmod $::g_loadedModuleConflict($modcon) {
             # skip own reflexive conflict (look at mod main and alternative
             # names) and those already known
-            if {![doesModuleMatchesName $mod $withmod] && ([set lmmodlist\
+            if {![doesModuleMatchesName $mod $withmod] && (!$isfullpath ||\
+               ![doesModuleMatchesName $smod $withmod]) && ([set lmmodlist\
                [getLoadedMatchingName $withmod returnall]] ne {} || [set\
                lmmodlist [getLoadedMatchingName $withmod returnall 1]] ne {})} {
                # multiple loaded module may match conflict declared name
@@ -4577,7 +4590,8 @@ proc doesModuleConflict {mod} {
       } elseif {[notInList $modconlist $modcon]} {
          foreach withmod $::g_loadedModuleConflict($modcon) {
             # check if mod or one of its alt name match conflict
-            if {[doesModuleMatchesName $mod $withmod]} {
+            if {[doesModuleMatchesName $mod $withmod] || ($isfullpath &&\
+               [doesModuleMatchesName $smod $withmod])} {
                lappend modconlist $modcon
                lappend moddecconlist $modcon
                set does 1
@@ -5966,7 +5980,7 @@ alias ml 'module ml \!*' ;}
 @quarantinesupport@      fi;
 @quarantinesupport@   done;
 @quarantinesupport@   if [ -n "${_mlre:-}" ]; then}
-@quarantinesupport@         append fdef "\n      eval `eval \${${wsplit}_mlre}$tclshbin $::argv0\
+@quarantinesupport@         append fdef "\n      eval `eval \${${wsplit}_mlre} $tclshbin $::argv0\
 @quarantinesupport@$::g_shell '\"\$@\"'`;
 @quarantinesupport@   else
 @quarantinesupport@      eval `$tclshbin $::argv0 $::g_shell \"\$@\"`;
@@ -9470,11 +9484,16 @@ proc cmdModuleSwitch {uasked old {new {}}} {
    # mentionned on this module switch command set in a modulefile
    set orig_auto_handling [getConf auto_handling]
    if {!$uasked && $argold ne {}} {
-      # temporarily disable auto handling just to record deps, not to try to
-      # load or unload them (already tried)
-      setConf auto_handling 0
-      catch {conflict $argold}
-      setConf auto_handling $orig_auto_handling
+      # skip conflict declaration if old spec matches new as in this case
+      # switch means *replace loaded version of mod by this specific version*
+      lassign [getPathToModule $new] newmodfile newmod
+      if {$newmod eq {} || ![modEq $argold $newmod eqstart]} {
+         # temporarily disable auto handling just to record deps, not to try
+         # to load or unload them (already tried)
+         setConf auto_handling 0
+         catch {conflict $argold}
+         setConf auto_handling $orig_auto_handling
+      }
    }
 
    # attempt load and depre reload only if unload succeed
diff --git a/script/mpub b/script/mpub
index 6c1c99399..b9b2e5d44 100755
--- a/script/mpub
+++ b/script/mpub
@@ -59,6 +59,14 @@ set cwd [pwd]
 set logfile mpub.out
 set logfid [open $logfile w]
 
+# get current branch
+set relbranch [exec git branch --show-current]
+if {[regexp {^(master|v\d+.\d+.x)$} $relbranch]} {
+   reportInfo "Found branch '$relbranch'"
+} else {
+   error "git branch '$relbranch' is not a valid release branch"
+}
+
 # ensure head sit on a tag
 set reltag [exec git describe --tags --exact-match]
 reportInfo "Found release tag '$reltag'"
@@ -111,11 +119,11 @@ set distwin modules-$relver-win.zip
 # ---------------------------------------------------------
 
 runcmd 2>@$logfid git push $sfremote c-3.2
-runcmd 2>@$logfid git push $sfremote master
+runcmd 2>@$logfid git push $sfremote $relbranch
 runcmd 2>@$logfid git push $sfremote $reltag
 
 runcmd 2>@$logfid git push $ghremote c-3.2
-runcmd 2>@$logfid git push $ghremote master
+runcmd 2>@$logfid git push $ghremote $relbranch
 runcmd 2>@$logfid git push $ghremote $reltag
 
 
@@ -156,7 +164,7 @@ file delete dlcheck
 
 if {[catch {runcmd make distclean} errmsg]} {
    # skip error if things have already been cleaned up
-   ignoreexp $errmsg {Makefile:38: *** Makefile.inc is missing, please run\
+   ignoreexp $errmsg {Makefile:37: *** Makefile.inc is missing, please run\
       './configure'.  Stop.}
 }
 runcmd 2>@$logfid git checkout gh-pages
@@ -180,7 +188,7 @@ close $fid
 runcmd sftp -o BatchMode=yes -b mpubbatch web.sourceforge.net
 file delete mpubbatch
 
-runcmd 2>@$logfid git checkout master
+runcmd 2>@$logfid git checkout $relbranch
 
 
 # everythings done, clean file transmitted by mrel
diff --git a/script/mrel b/script/mrel
index 60de598b2..98969bf79 100755
--- a/script/mrel
+++ b/script/mrel
@@ -82,6 +82,14 @@ set cwd [pwd]
 set logfile mrel.out
 set logfid [open $logfile w]
 
+# get current branch
+set relbranch [exec git branch --show-current]
+if {[regexp {^(master|v\d+.\d+.x)$} $relbranch]} {
+   reportInfo "Found branch '$relbranch'"
+} else {
+   error "git branch '$relbranch' is not a valid release branch"
+}
+
 # ensure head sit on a tag
 set reltag [exec git describe --tags --exact-match]
 reportInfo "Found release tag '$reltag'"
@@ -130,8 +138,8 @@ if {![info exists env(MREL_GITHUB_TEST_REMOTE)]} {
 set gh_test_remote $env(MREL_GITHUB_TEST_REMOTE)
 reportInfo "GitHub test remote set to '$gh_test_remote'"
 set ghremtgt [lindex [split [exec git remote get-url $gh_test_remote] :.] 2]
-set ghstatusurl https://api.github.com/repos/$ghremtgt/commits/master/status
-set ghtgturl https://github.com/$ghremtgt/commit/master
+set ghstatusurl https://api.github.com/repos/$ghremtgt/commits/$relbranch/status
+set ghtgturl https://github.com/$ghremtgt/commit/$relbranch
 set ghcloneurl https://github.com/$ghremtgt.git
 set ghexporturl https://github.com/$ghremtgt/archive/$reltag.tar.gz
 
@@ -146,6 +154,10 @@ foreach oldsrpm [glob -nocomplain $srpmdir/environment-modules-*.src.rpm] {
    reportInfo "Delete previous SRPM '$oldsrpm'"
    file delete $oldsrpm
 }
+foreach oldrpm [glob -nocomplain $rpmdir/environment-modules-*.rpm] {
+   reportInfo "Delete previous RPM '$oldrpm'"
+   file delete $oldrpm
+}
 
 # remove installed RPMs or dist
 catch {runcmd 2>@$logfid sudo rpm -e --nodeps scl-utils}
@@ -159,7 +171,7 @@ runcmd sudo rm -rf /usr/local/Modules
 
 if {[catch {runcmd make distclean} errmsg]} {
    # skip error if things have already been cleaned up
-   ignoreexp $errmsg {Makefile:38: *** Makefile.inc is missing, please run\
+   ignoreexp $errmsg {Makefile:37: *** Makefile.inc is missing, please run\
       './configure'.  Stop.}
 }
 if {[catch {runcmd ./configure} errmsg]} {
@@ -233,7 +245,7 @@ quitorcont
 # ---------------------------------------------------------
 
 runcmd 2>@$logfid git push --force $gh_test_remote c-3.2
-runcmd 2>@$logfid git push --force $gh_test_remote master
+runcmd 2>@$logfid git push --force $gh_test_remote $relbranch
 runcmd 2>@$logfid git push --force $gh_test_remote $reltag
 # see Phase 7 for CI result check
 
@@ -279,6 +291,7 @@ cd /tmp/mods+test-clone
 runcmd 2>@$logfid git clone $ghcloneurl
 cd modules
 reportInfo "Moved into '[pwd]' directory"
+runcmd 2>@$logfid git checkout $relbranch
 runcmd 2>@$logfid ./configure
 runcmd make
 runcmd 2>@$logfid script/mt
@@ -348,7 +361,7 @@ while {[array size koji_tasks] > 0} {
          set koji_out [exec koji taskinfo $ktask]
          regexp {State: (\w+)} $koji_out match kstate
          switch -- $kstate {
-            open {
+            free - open {
                reportInfo "Task '$ktask' on '$koji_tasks($ktask)' still\
                   running"
             }
diff --git a/testsuite/install.00-init/060-quar.exp b/testsuite/install.00-init/060-quar.exp
index ed0beed51..8cd3d1269 100644
--- a/testsuite/install.00-init/060-quar.exp
+++ b/testsuite/install.00-init/060-quar.exp
@@ -29,6 +29,12 @@ if {$install_quarantinevars ne ""} {
 set ans [list]
 set ansr [list]
 
+# if test set LD_PRELOAD to a non-existent lib, ld will shout error
+if {[lsearch -exact $install_quarlist LD_PRELOAD] != -1} {
+   lappend ans "(ERROR: ld.so: object 'foo'.*)*"
+   lappend ansr "(ERROR: ld.so: object 'foo'.*)*"
+}
+
 set quar [join $install_quarlist " "]
 if { $verbose > 0 } {
    send_user "\tAlready configured MODULES_RUN_QUARANTINE = '$quar'\n"
@@ -70,7 +76,7 @@ foreach shell $shell_list {
          }
       }
       default {
-         testall_cmd "$shell" "module source $modfile" "" [join $ans "\n"] 0
+         testall_cmd_re "$shell" "module source $modfile" "" [join $ans "\n"] 0
       }
    }
 }
@@ -81,7 +87,7 @@ foreach shell $othlang_list {
          testall_cmd_re "$shell" "source,$modfile" "" [join $ansr "\n"] 0
       }
       default {
-         testall_cmd "$shell" "source,$modfile" "" [join $ans "\n"] 0
+         testall_cmd_re "$shell" "source,$modfile" "" [join $ans "\n"] 0
       }
    }
 }
@@ -90,6 +96,10 @@ foreach shell $othlang_list {
 #  Clean up variables used in this test case
 #
 
+foreach vname $install_quarlist {
+   unset env($vname)
+}
+
 if {[info exists vname]} {
    unset vname
 }
diff --git a/testsuite/modulefiles.deps/swaa/1.0 b/testsuite/modulefiles.deps/swaa/1.0
new file mode 100644
index 000000000..1c148cdd2
--- /dev/null
+++ b/testsuite/modulefiles.deps/swaa/1.0
@@ -0,0 +1 @@
+#%Module
diff --git a/testsuite/modulefiles.deps/swaa/1.1 b/testsuite/modulefiles.deps/swaa/1.1
new file mode 100644
index 000000000..1c148cdd2
--- /dev/null
+++ b/testsuite/modulefiles.deps/swaa/1.1
@@ -0,0 +1 @@
+#%Module
diff --git a/testsuite/modulefiles.deps/swaa/1.2 b/testsuite/modulefiles.deps/swaa/1.2
new file mode 100644
index 000000000..1c148cdd2
--- /dev/null
+++ b/testsuite/modulefiles.deps/swaa/1.2
@@ -0,0 +1 @@
+#%Module
diff --git a/testsuite/modulefiles.deps/swaa/1.4 b/testsuite/modulefiles.deps/swaa/1.4
new file mode 100644
index 000000000..1c148cdd2
--- /dev/null
+++ b/testsuite/modulefiles.deps/swaa/1.4
@@ -0,0 +1 @@
+#%Module
diff --git a/testsuite/modulefiles.deps/swaa/2/0 b/testsuite/modulefiles.deps/swaa/2/0
new file mode 100644
index 000000000..1c148cdd2
--- /dev/null
+++ b/testsuite/modulefiles.deps/swaa/2/0
@@ -0,0 +1 @@
+#%Module
diff --git a/testsuite/modulefiles.deps/swaa/2/2 b/testsuite/modulefiles.deps/swaa/2/2
new file mode 100644
index 000000000..1c148cdd2
--- /dev/null
+++ b/testsuite/modulefiles.deps/swaa/2/2
@@ -0,0 +1 @@
+#%Module
diff --git a/testsuite/modulefiles.deps/swaa/2/8 b/testsuite/modulefiles.deps/swaa/2/8
new file mode 100644
index 000000000..1c148cdd2
--- /dev/null
+++ b/testsuite/modulefiles.deps/swaa/2/8
@@ -0,0 +1 @@
+#%Module
diff --git a/testsuite/modulefiles.deps/swaa/3.0 b/testsuite/modulefiles.deps/swaa/3.0
new file mode 100644
index 000000000..1c148cdd2
--- /dev/null
+++ b/testsuite/modulefiles.deps/swaa/3.0
@@ -0,0 +1 @@
+#%Module
diff --git a/testsuite/modulefiles.deps/swaa/3.2 b/testsuite/modulefiles.deps/swaa/3.2
new file mode 100644
index 000000000..1c148cdd2
--- /dev/null
+++ b/testsuite/modulefiles.deps/swaa/3.2
@@ -0,0 +1 @@
+#%Module
diff --git a/testsuite/modulefiles.deps/swaa/3.8 b/testsuite/modulefiles.deps/swaa/3.8
new file mode 100644
index 000000000..1c148cdd2
--- /dev/null
+++ b/testsuite/modulefiles.deps/swaa/3.8
@@ -0,0 +1 @@
+#%Module
diff --git a/testsuite/modulefiles.deps/swab b/testsuite/modulefiles.deps/swab
new file mode 100644
index 000000000..f9ded1cfa
--- /dev/null
+++ b/testsuite/modulefiles.deps/swab
@@ -0,0 +1,50 @@
+#%Module
+
+if {[info exists env(TESTSUITE_SWAA_SWITCH_SET1)]} {
+    module switch swaa swaa/3.8
+}
+if {[info exists env(TESTSUITE_SWAA_SWITCH_SET2)]} {
+    module switch swaa swaa@3
+}
+if {[info exists env(TESTSUITE_SWAA_SWITCH_SET3)]} {
+    module switch swaa@3 swaa@3.2:
+}
+if {[info exists env(TESTSUITE_SWAA_SWITCH_SET4)]} {
+    module switch swaa@1 swaa@3.2:
+}
+if {[info exists env(TESTSUITE_SWAA_SWITCH_SET5)]} {
+    module switch swaa/1 swaa@3.2:
+}
+if {[info exists env(TESTSUITE_SWAA_SWITCH_SET6)]} {
+    module switch swaa@1 swaa@3.8
+}
+if {[info exists env(TESTSUITE_SWAA_SWITCH_SET7)]} {
+    module switch swaa@1 swaa/3.8
+}
+if {[info exists env(TESTSUITE_SWAA_SWITCH_SET8)]} {
+    module switch swaa@1: swaa@3.8
+}
+if {[info exists env(TESTSUITE_SWAA_SWITCH_SET9)]} {
+    module switch swaa@2 swaa@3
+}
+if {[info exists env(TESTSUITE_SWAA_SWITCH_SET10)]} {
+    module switch swaa/2@:6 swaa@3
+}
+if {[info exists env(TESTSUITE_SWAA_SWITCH_SET11)]} {
+    module switch swaa/2@0,8 swaa/3
+}
+if {[info exists env(TESTSUITE_SWAA_SWITCH_SET12)]} {
+    module switch swaa@1 swaa@2
+}
+if {[info exists env(TESTSUITE_SWAA_SWITCH_SET13)]} {
+    module switch swaa@1 swaa/2@6:
+}
+if {[info exists env(TESTSUITE_SWAA_SWITCH_SET14)]} {
+    module switch swaa/2@0,8 swaa
+}
+if {[info exists env(TESTSUITE_SWAA_SWITCH_SET15)]} {
+    module switch swaa/2@6: swaa@2
+}
+if {[info exists env(TESTSUITE_SWAA_SWITCH_SET16)]} {
+    module switch swaa/2@6: swaa/2@:6
+}
diff --git a/testsuite/modules.50-cmds/370-deps-fullpath.exp b/testsuite/modules.50-cmds/370-deps-fullpath.exp
new file mode 100644
index 000000000..10b335c13
--- /dev/null
+++ b/testsuite/modules.50-cmds/370-deps-fullpath.exp
@@ -0,0 +1,117 @@
+##############################################################################
+#   Modules Revision 3.0
+#   Providing a flexible user environment
+#
+#   File:		modules.50-cmds/%M%
+#   Revision:		%I%
+#   First Edition:	2020/07/29
+#   Last Mod.:		%U%, %G%
+#
+#   Authors:		Xavier Delaruelle, xavier.delaruelle@cea.fr
+#
+#   Description:	Testuite testsequence
+#   Command:        load, unload
+#   Modulefiles:
+#   Sub-Command:    prereq, conflict
+#
+#   Comment:	%C{
+#           Test resolution of modulefile dependencies when module are
+#           loaded with their full pathname.
+#		}C%
+#
+##############################################################################
+
+# disable auto_handling with environment variable
+setenv_var MODULES_AUTO_HANDLING 0
+
+set mp "$modpath.deps"
+set mpre "$modpathre.deps"
+
+# setup specific environment
+setenv_path_var MODULEPATH $mp
+
+
+# reflexive conflict
+set ans [list]
+lappend ans [list setpath LOADEDMODULES $mp/c]
+lappend ans [list setpath _LMFILES_ $mp/c]
+lappend ans [list setpath MODULES_LMCONFLICT $mp/c&c]
+testouterr_cmd sh "load $mp/c" $ans {}
+testouterr_cmd sh "load --auto $mp/c" $ans {}
+
+setenv_loaded_module [list c] [list $mp/c]
+setenv_path_var MODULES_LMCONFLICT c&c
+set ans [list]
+lappend ans [list setpath LOADEDMODULES c:$mp/b]
+lappend ans [list setpath _LMFILES_ $mp/c:$mp/b]
+lappend ans [list setpath MODULES_LMPREREQ $mp/b&c]
+testouterr_cmd_re sh "load $mp/b" $ans {}
+
+setenv_loaded_module [list $mp/c] [list $mp/c]
+setenv_path_var MODULES_LMCONFLICT $mp/c&c
+testouterr_cmd_re sh "load c" OK {}
+
+set ans [list]
+lappend ans [list unsetpath LOADEDMODULES]
+lappend ans [list unsetpath _LMFILES_]
+lappend ans [list unsetpath MODULES_LMCONFLICT]
+testouterr_cmd_re sh "unload c" $ans {}
+testouterr_cmd_re sh "unload $mp/c" $ans {}
+testouterr_cmd_re sh "unload --auto c" $ans {}
+testouterr_cmd_re sh "unload --auto $mp/c" $ans {}
+
+# requirement
+setenv_loaded_module [list $mp/c] [list $mp/c]
+setenv_path_var MODULES_LMCONFLICT $mp/c&c
+set ans [list]
+lappend ans [list setpath LOADEDMODULES $mp/c:b]
+lappend ans [list setpath _LMFILES_ $mp/c:$mp/b]
+lappend ans [list setpath MODULES_LMPREREQ b&c]
+testouterr_cmd_re sh "load b" $ans {}
+testouterr_cmd_re sh "load --auto b" $ans {}
+set ans [list]
+lappend ans [list setpath LOADEDMODULES $mp/c:$mp/b]
+lappend ans [list setpath _LMFILES_ $mp/c:$mp/b]
+lappend ans [list setpath MODULES_LMPREREQ $mp/b&c]
+testouterr_cmd_re sh "load $mp/b" $ans {}
+testouterr_cmd_re sh "load --auto $mp/b" $ans {}
+
+# conflict
+setenv_loaded_module [list $mp/c:$mp/b] [list $mp/c:$mp/b]
+setenv_path_var MODULES_LMCONFLICT $mp/c&c
+setenv_path_var MODULES_LMPREREQ $mp/b&c
+testouterr_cmd sh "load a" ERR [msg_load a [err_conflict a b]]
+testouterr_cmd sh "load --auto a" ERR [msg_load a [err_conflict a b]]
+testouterr_cmd sh "load $mp/a" ERR [msg_load $mp/a [err_conflict $mp/a b]]
+testouterr_cmd sh "load --auto $mp/a" ERR [msg_load $mp/a [err_conflict $mp/a b]]
+
+# force conflict
+set ans [list]
+lappend ans [list setpath LOADEDMODULES $mp/c:$mp/b:a]
+lappend ans [list setpath _LMFILES_ $mp/c:$mp/b:$mp/a]
+lappend ans [list setpath MODULES_LMCONFLICT $mp/c&c:a&b]
+testouterr_cmd_re sh "load --force a" $ans [msg_load a [err_conlof b]]
+testouterr_cmd_re sh "load --auto --force a" $ans [msg_load a [err_conlof b]]
+set ans [list]
+lappend ans [list setpath LOADEDMODULES $mp/c:$mp/b:$mp/a]
+lappend ans [list setpath _LMFILES_ $mp/c:$mp/b:$mp/a]
+lappend ans [list setpath MODULES_LMCONFLICT $mp/c&c:$mp/a&b]
+testouterr_cmd_re sh "load --force $mp/a" $ans [msg_load $mpre/a [err_conlof b]]
+testouterr_cmd_re sh "load --auto --force $mp/a" $ans [msg_load $mpre/a [err_conlof b]]
+
+
+#
+#  Cleanup
+#
+
+# restore environment
+setenv_path_var MODULEPATH $modpath
+unsetenv_path_var MODULES_LMCONFLICT
+unsetenv_path_var MODULES_LMPREREQ
+unsetenv_loaded_module
+
+unsetenv_var MODULES_AUTO_HANDLING
+
+unset mp
+unset mpre
+unset ans
diff --git a/testsuite/modules.50-cmds/376-switch-change-vers.exp b/testsuite/modules.50-cmds/376-switch-change-vers.exp
new file mode 100644
index 000000000..33ccdac11
--- /dev/null
+++ b/testsuite/modules.50-cmds/376-switch-change-vers.exp
@@ -0,0 +1,318 @@
+##############################################################################
+#   Modules Revision 3.0
+#   Providing a flexible user environment
+#
+#   File:		modules.50-cmds/%M%
+#   Revision:		%I%
+#   First Edition:	2020/08/10
+#   Last Mod.:		%U%, %G%
+#
+#   Authors:		Xavier Delaruelle, xavier.delaruelle@cea.fr
+#
+#   Description:	Testuite testsequence
+#   Command:        load
+#   Modulefiles:
+#   Sub-Command:    module switch
+#
+#   Comment:	%C{
+#           Test automatic resolution of modulefile dependencies defined
+#           through 'module switch' command in modulefiles where swaped-off
+#           module spec matches swaped-on module
+#		}C%
+#
+##############################################################################
+
+# CAUTION: it is not recommended to use the `switch` sub-command in
+# modulefiles as this command is intended for the command-line for a 2in1
+# operation. Could be removed from the modulefile scope in a future
+# release. Use `module unload` and `module load` commands in modulefiles
+# instead.
+
+# skip tests if implicit_default option could not be overridden
+if {[is_config_locked implicit_default]} {
+    send_user "\tskipping tests as implicit_default could not be overridden\n"
+} else {
+
+set mp $modpath.deps
+set mpre $modpathre.deps
+
+# setup specific environment
+setenv_path_var MODULEPATH $mp
+
+# ensure load tests have implicit default enabled
+setenv_var MODULES_IMPLICIT_DEFAULT 1
+
+# ensure advanced version specifiers are enabled for these tests
+setenv_var MODULES_ADVANCED_VERSION_SPEC 1
+
+
+# module switch swaa swaa/3.8
+setenv_var TESTSUITE_SWAA_SWITCH_SET1 1
+unsetenv_loaded_module
+set ans [list]
+lappend ans [list setpath LOADEDMODULES swaa/3.8:swab]
+lappend ans [list setpath _LMFILES_ $mp/swaa/3.8:$mp/swab]
+lappend ans [list setpath MODULES_LMPREREQ swab&swaa/3.8]
+lappend ans [list setpath MODULES_LMNOTUASKED swaa/3.8]
+lappend ans [list setpath MODULES_LMALTNAME swaa/3.8&as|swaa/default&as|swaa/latest]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab {} swaa/3.8 {}]
+
+setenv_loaded_module [list swaa/1.2] [list $mp/swaa/1.2]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab swaa/1.2 swaa/3.8 {}]
+unsetenv_var TESTSUITE_SWAA_SWITCH_SET1
+
+# ensure extended default is enabled for the remaining tests
+setenv_var MODULES_EXTENDED_DEFAULT 1
+
+# module switch swaa swaa@3
+setenv_var TESTSUITE_SWAA_SWITCH_SET2 1
+unsetenv_loaded_module
+set ans [list]
+lappend ans [list setpath LOADEDMODULES swaa/3.8:swab]
+lappend ans [list setpath _LMFILES_ $mp/swaa/3.8:$mp/swab]
+lappend ans [list setpath MODULES_LMPREREQ swab&swaa@3]
+lappend ans [list setpath MODULES_LMNOTUASKED swaa/3.8]
+lappend ans [list setpath MODULES_LMALTNAME swaa/3.8&as|swaa/default&as|swaa/latest]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab {} swaa/3.8 {}]
+
+setenv_loaded_module [list swaa/1.2] [list $mp/swaa/1.2]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab swaa/1.2 swaa/3.8 {}]
+unsetenv_var TESTSUITE_SWAA_SWITCH_SET2
+
+# module switch swaa@3 swaa@3.2:
+setenv_var TESTSUITE_SWAA_SWITCH_SET3 1
+unsetenv_loaded_module
+set ans [list]
+lappend ans [list setpath LOADEDMODULES swaa/3.8:swab]
+lappend ans [list setpath _LMFILES_ $mp/swaa/3.8:$mp/swab]
+lappend ans [list setpath MODULES_LMPREREQ swab&swaa@3.2<]
+lappend ans [list setpath MODULES_LMNOTUASKED swaa/3.8]
+lappend ans [list setpath MODULES_LMALTNAME swaa/3.8&as|swaa/default&as|swaa/latest]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab {} swaa/3.8 {}]
+
+setenv_loaded_module [list swaa/3.2] [list $mp/swaa/3.2]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab swaa/3.2 swaa/3.8 {}]
+unsetenv_var TESTSUITE_SWAA_SWITCH_SET3
+
+# module switch swaa@1 swaa@3.2:
+setenv_var TESTSUITE_SWAA_SWITCH_SET4 1
+unsetenv_loaded_module
+set ans [list]
+lappend ans [list setpath LOADEDMODULES swaa/3.8:swab]
+lappend ans [list setpath _LMFILES_ $mp/swaa/3.8:$mp/swab]
+lappend ans [list setpath MODULES_LMALTNAME swaa/3.8&as|swaa/default&as|swaa/latest]
+lappend ans [list setpath MODULES_LMPREREQ swab&swaa@3.2<]
+lappend ans [list setpath MODULES_LMCONFLICT swab&swaa@1]
+lappend ans [list setpath MODULES_LMNOTUASKED swaa/3.8]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab {} swaa/3.8 {}]
+
+setenv_loaded_module [list swaa/1.2] [list $mp/swaa/1.2]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab swaa/1.2 swaa/3.8 {}]
+unsetenv_var TESTSUITE_SWAA_SWITCH_SET4
+
+# module switch swaa/1 swaa@3.2:
+setenv_var TESTSUITE_SWAA_SWITCH_SET5 1
+unsetenv_loaded_module
+set ans [list]
+lappend ans [list setpath LOADEDMODULES swaa/3.8:swab]
+lappend ans [list setpath _LMFILES_ $mp/swaa/3.8:$mp/swab]
+lappend ans [list setpath MODULES_LMALTNAME swaa/3.8&as|swaa/default&as|swaa/latest]
+lappend ans [list setpath MODULES_LMPREREQ swab&swaa@3.2<]
+lappend ans [list setpath MODULES_LMCONFLICT swab&swaa/1]
+lappend ans [list setpath MODULES_LMNOTUASKED swaa/3.8]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab {} swaa/3.8 {}]
+
+setenv_loaded_module [list swaa/1.2] [list $mp/swaa/1.2]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab swaa/1.2 swaa/3.8 {}]
+unsetenv_var TESTSUITE_SWAA_SWITCH_SET5
+
+# module switch swaa@1 swaa@3.8
+setenv_var TESTSUITE_SWAA_SWITCH_SET6 1
+unsetenv_loaded_module
+set ans [list]
+lappend ans [list setpath LOADEDMODULES swaa/3.8:swab]
+lappend ans [list setpath _LMFILES_ $mp/swaa/3.8:$mp/swab]
+lappend ans [list setpath MODULES_LMALTNAME swaa/3.8&as|swaa/default&as|swaa/latest]
+lappend ans [list setpath MODULES_LMPREREQ swab&swaa@3.8]
+lappend ans [list setpath MODULES_LMCONFLICT swab&swaa@1]
+lappend ans [list setpath MODULES_LMNOTUASKED swaa/3.8]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab {} swaa/3.8 {}]
+
+setenv_loaded_module [list swaa/1.2] [list $mp/swaa/1.2]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab swaa/1.2 swaa/3.8 {}]
+unsetenv_var TESTSUITE_SWAA_SWITCH_SET6
+
+# module switch swaa@1 swaa/3.8
+setenv_var TESTSUITE_SWAA_SWITCH_SET7 1
+unsetenv_loaded_module
+set ans [list]
+lappend ans [list setpath LOADEDMODULES swaa/3.8:swab]
+lappend ans [list setpath _LMFILES_ $mp/swaa/3.8:$mp/swab]
+lappend ans [list setpath MODULES_LMALTNAME swaa/3.8&as|swaa/default&as|swaa/latest]
+lappend ans [list setpath MODULES_LMPREREQ swab&swaa/3.8]
+lappend ans [list setpath MODULES_LMCONFLICT swab&swaa@1]
+lappend ans [list setpath MODULES_LMNOTUASKED swaa/3.8]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab {} swaa/3.8 {}]
+
+setenv_loaded_module [list swaa/1.2] [list $mp/swaa/1.2]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab swaa/1.2 swaa/3.8 {}]
+unsetenv_var TESTSUITE_SWAA_SWITCH_SET7
+
+# module switch swaa@1: swaa@3.8
+setenv_var TESTSUITE_SWAA_SWITCH_SET8 1
+unsetenv_loaded_module
+set ans [list]
+lappend ans [list setpath LOADEDMODULES swaa/3.8:swab]
+lappend ans [list setpath _LMFILES_ $mp/swaa/3.8:$mp/swab]
+lappend ans [list setpath MODULES_LMPREREQ swab&swaa@3.8]
+lappend ans [list setpath MODULES_LMNOTUASKED swaa/3.8]
+lappend ans [list setpath MODULES_LMALTNAME swaa/3.8&as|swaa/default&as|swaa/latest]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab {} swaa/3.8 {}]
+
+setenv_loaded_module [list swaa/3.0] [list $mp/swaa/3.0]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab swaa/3.0 swaa/3.8 {}]
+unsetenv_var TESTSUITE_SWAA_SWITCH_SET8
+
+# module switch swaa@2 swaa@3
+setenv_var TESTSUITE_SWAA_SWITCH_SET9 1
+unsetenv_loaded_module
+set ans [list]
+lappend ans [list setpath LOADEDMODULES swaa/3.8:swab]
+lappend ans [list setpath _LMFILES_ $mp/swaa/3.8:$mp/swab]
+lappend ans [list setpath MODULES_LMALTNAME swaa/3.8&as|swaa/default&as|swaa/latest]
+lappend ans [list setpath MODULES_LMPREREQ swab&swaa@3]
+lappend ans [list setpath MODULES_LMCONFLICT swab&swaa@2]
+lappend ans [list setpath MODULES_LMNOTUASKED swaa/3.8]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab {} swaa/3.8 {}]
+
+setenv_loaded_module [list swaa/2/0] [list $mp/swaa/2/0]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab swaa/2/0 swaa/3.8 {}]
+unsetenv_var TESTSUITE_SWAA_SWITCH_SET9
+
+# module switch swaa/2@:6 swaa@3
+setenv_var TESTSUITE_SWAA_SWITCH_SET10 1
+unsetenv_loaded_module
+set ans [list]
+lappend ans [list setpath LOADEDMODULES swaa/3.8:swab]
+lappend ans [list setpath _LMFILES_ $mp/swaa/3.8:$mp/swab]
+lappend ans [list setpath MODULES_LMALTNAME swaa/3.8&as|swaa/default&as|swaa/latest]
+lappend ans [list setpath MODULES_LMPREREQ swab&swaa@3]
+lappend ans [list setpath MODULES_LMCONFLICT swab&swaa/2@<6]
+lappend ans [list setpath MODULES_LMNOTUASKED swaa/3.8]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab {} swaa/3.8 {}]
+
+setenv_loaded_module [list swaa/2/2] [list $mp/swaa/2/2]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab swaa/2/2 swaa/3.8 {}]
+unsetenv_var TESTSUITE_SWAA_SWITCH_SET10
+
+# module switch swaa/2@0,8 swaa/3
+setenv_var TESTSUITE_SWAA_SWITCH_SET11 1
+unsetenv_loaded_module
+set ans [list]
+lappend ans [list setpath LOADEDMODULES swaa/3.8:swab]
+lappend ans [list setpath _LMFILES_ $mp/swaa/3.8:$mp/swab]
+lappend ans [list setpath MODULES_LMALTNAME swaa/3.8&as|swaa/default&as|swaa/latest]
+lappend ans [list setpath MODULES_LMPREREQ swab&swaa/3]
+lappend ans [list setpath MODULES_LMCONFLICT swab&swaa/2@0,8]
+lappend ans [list setpath MODULES_LMNOTUASKED swaa/3.8]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab {} swaa/3.8 {}]
+
+setenv_loaded_module [list swaa/2/8] [list $mp/swaa/2/8]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab swaa/2/8 swaa/3.8 {}]
+unsetenv_var TESTSUITE_SWAA_SWITCH_SET11
+
+# module switch swaa@1 swaa@2
+setenv_var TESTSUITE_SWAA_SWITCH_SET12 1
+unsetenv_loaded_module
+set ans [list]
+lappend ans [list setpath LOADEDMODULES swaa/2/8:swab]
+lappend ans [list setpath _LMFILES_ $mp/swaa/2/8:$mp/swab]
+lappend ans [list setpath MODULES_LMALTNAME swaa/2/8&as|swaa/2/default&as|swaa/2/latest]
+lappend ans [list setpath MODULES_LMPREREQ swab&swaa@2]
+lappend ans [list setpath MODULES_LMCONFLICT swab&swaa@1]
+lappend ans [list setpath MODULES_LMNOTUASKED swaa/2/8]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab {} swaa/2/8 {}]
+
+setenv_loaded_module [list swaa/1.2] [list $mp/swaa/1.2]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab swaa/1.2 swaa/2/8 {}]
+unsetenv_var TESTSUITE_SWAA_SWITCH_SET12
+
+# module switch swaa@1 swaa/2@6:
+setenv_var TESTSUITE_SWAA_SWITCH_SET13 1
+unsetenv_loaded_module
+set ans [list]
+lappend ans [list setpath LOADEDMODULES swaa/2/8:swab]
+lappend ans [list setpath _LMFILES_ $mp/swaa/2/8:$mp/swab]
+lappend ans [list setpath MODULES_LMALTNAME swaa/2/8&as|swaa/2/default&as|swaa/2/latest]
+lappend ans [list setpath MODULES_LMPREREQ swab&swaa/2@6<]
+lappend ans [list setpath MODULES_LMCONFLICT swab&swaa@1]
+lappend ans [list setpath MODULES_LMNOTUASKED swaa/2/8]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab {} swaa/2/8 {}]
+
+setenv_loaded_module [list swaa/1.2] [list $mp/swaa/1.2]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab swaa/1.2 swaa/2/8 {}]
+unsetenv_var TESTSUITE_SWAA_SWITCH_SET13
+
+# module switch swaa/2@0,8 swaa
+setenv_var TESTSUITE_SWAA_SWITCH_SET14 1
+unsetenv_loaded_module
+set ans [list]
+lappend ans [list setpath LOADEDMODULES swaa/3.8:swab]
+lappend ans [list setpath _LMFILES_ $mp/swaa/3.8:$mp/swab]
+lappend ans [list setpath MODULES_LMALTNAME swaa/3.8&as|swaa/default&as|swaa/latest]
+lappend ans [list setpath MODULES_LMPREREQ swab&swaa]
+lappend ans [list setpath MODULES_LMCONFLICT swab&swaa/2@0,8]
+lappend ans [list setpath MODULES_LMNOTUASKED swaa/3.8]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab {} swaa/3.8 {}]
+
+setenv_loaded_module [list swaa/2/0] [list $mp/swaa/2/0]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab swaa/2/0 swaa/3.8 {}]
+unsetenv_var TESTSUITE_SWAA_SWITCH_SET14
+
+# module switch swaa/2@6: swaa@2
+setenv_var TESTSUITE_SWAA_SWITCH_SET15 1
+unsetenv_loaded_module
+set ans [list]
+lappend ans [list setpath LOADEDMODULES swaa/2/8:swab]
+lappend ans [list setpath _LMFILES_ $mp/swaa/2/8:$mp/swab]
+lappend ans [list setpath MODULES_LMPREREQ swab&swaa@2]
+lappend ans [list setpath MODULES_LMNOTUASKED swaa/2/8]
+lappend ans [list setpath MODULES_LMALTNAME swaa/2/8&as|swaa/2/default&as|swaa/2/latest]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab {} swaa/2/8 {}]
+
+setenv_loaded_module [list swaa/2/8] [list $mp/swaa/2/8]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab swaa/2/8 swaa/2/8 {}]
+unsetenv_var TESTSUITE_SWAA_SWITCH_SET15
+
+# module switch swaa/2@6: swaa/2@:6
+setenv_var TESTSUITE_SWAA_SWITCH_SET16 1
+unsetenv_loaded_module
+set ans [list]
+lappend ans [list setpath LOADEDMODULES swaa/2/2:swab]
+lappend ans [list setpath _LMFILES_ $mp/swaa/2/2:$mp/swab]
+lappend ans [list setpath MODULES_LMPREREQ swab&swaa/2@<6]
+lappend ans [list setpath MODULES_LMNOTUASKED swaa/2/2]
+lappend ans [list setpath MODULES_LMCONFLICT swab&swaa/2@6<]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab {} swaa/2/2 {}]
+
+setenv_loaded_module [list swaa/2/8] [list $mp/swaa/2/8]
+testouterr_cmd_re sh {load swab} $ans [msg_top_load swab swaa/2/8 swaa/2/2 {}]
+unsetenv_var TESTSUITE_SWAA_SWITCH_SET16
+
+
+#
+#  Cleanup
+#
+
+# restore environment
+unsetenv_loaded_module
+setenv_path_var MODULEPATH $modpath
+unsetenv_var MODULES_IMPLICIT_DEFAULT
+unsetenv_var MODULES_ADVANCED_VERSION_SPEC
+unsetenv_var MODULES_EXTENDED_DEFAULT
+
+unset mp
+unset mpre
+unset ans
+
+}
diff --git a/testsuite/modules.70-maint/120-autoinit.exp b/testsuite/modules.70-maint/120-autoinit.exp
index 83744a8d5..078660cee 100644
--- a/testsuite/modules.70-maint/120-autoinit.exp
+++ b/testsuite/modules.70-maint/120-autoinit.exp
@@ -170,22 +170,22 @@ set func_end "\\s*_mlstatus=\\\$\\\?;\n$func_clean_ifs$end_silentdbg\\s*return \
 
 if {$install_quarantinesupport eq y} {
 set func_modcmd_sh "\\s*if \\\[ -n \"\\\${_mlre:-}\" \\\]; then
-\\s*eval `eval \\\${_mlre}$tclshlocre $modulecmd_pathre sh '\"\\$\\@\"'`;
+\\s*eval `eval \\\${_mlre} $tclshlocre $modulecmd_pathre sh '\"\\$\\@\"'`;
 \\s*else
 \\s*eval `$tclshlocre $modulecmd_pathre sh \"\\$\\@\"`;
 \\s*fi;"
 set func_modcmd_bash "\\s*if \\\[ -n \"\\\${_mlre:-}\" \\\]; then
-\\s*eval `eval \\\${_mlre}$tclshlocre $modulecmd_pathre bash '\"\\$\\@\"'`;
+\\s*eval `eval \\\${_mlre} $tclshlocre $modulecmd_pathre bash '\"\\$\\@\"'`;
 \\s*else
 \\s*eval `$tclshlocre $modulecmd_pathre bash \"\\$\\@\"`;
 \\s*fi;"
 set func_modcmd_ksh "\\s*if \\\[ -n \"\\\${_mlre:-}\" \\\]; then
-\\s*eval `eval \\\${_mlre}$tclshlocre $modulecmd_pathre ksh '\"\\$\\@\"'`;
+\\s*eval `eval \\\${_mlre} $tclshlocre $modulecmd_pathre ksh '\"\\$\\@\"'`;
 \\s*else
 \\s*eval `$tclshlocre $modulecmd_pathre ksh \"\\$\\@\"`;
 \\s*fi;"
 set func_modcmd_zsh "\\s*if \\\[ -n \"\\\${_mlre:-}\" \\\]; then
-\\s*eval `eval \\\${=_mlre}$tclshlocre $modulecmd_pathre zsh '\"\\$\\@\"'`;
+\\s*eval `eval \\\${=_mlre} $tclshlocre $modulecmd_pathre zsh '\"\\$\\@\"'`;
 \\s*else
 \\s*eval `$tclshlocre $modulecmd_pathre zsh \"\\$\\@\"`;
 \\s*fi;"
diff --git a/testsuite/modules.70-maint/270-adv_version_spec.exp b/testsuite/modules.70-maint/270-adv_version_spec.exp
index 5d14b9cd4..812fc96f0 100644
--- a/testsuite/modules.70-maint/270-adv_version_spec.exp
+++ b/testsuite/modules.70-maint/270-adv_version_spec.exp
@@ -637,7 +637,7 @@ testouterr_cmd_re sh {load advvers2@7.0} $ans {}
 unsetenv_loaded_module
 
 # test unknown module
-testouterr_cmd sh {load --auto advvers2@8.1.1} ERR [msg_load advvers2/8.1.1 $err_path'unknown@1.4.5' [err_prereq advvers2/8.1.1 unknown@1.4.5]]
+testouterr_cmd sh {load --auto advvers2@8.1.1} ERR [msg_load advvers2/8.1.1 $err_path'unknown@1.4.5' [err_reqlo unknown@1.4.5]]
 set ans [list]
 lappend ans [list setpath LOADEDMODULES advvers2/8.1.2]
 lappend ans [list setpath _LMFILES_ $mp/advvers2/8.1.2]
@@ -658,9 +658,9 @@ testouterr_cmd sh {load --auto advvers2@8.2.2} ERR [msg_load advvers2/8.2.2 [msg
 unsetenv_loaded_module
 
 # test mod@vers where a modulefile mod@vers exist
-testouterr_cmd_re sh {load --auto advvers2@8.3.1} ERR [msg_load advvers2/8.3.1 $err_path'advvers@2.1' [err_prereq advvers2/8.3.1 advvers@2.1]]
+testouterr_cmd_re sh {load --auto advvers2@8.3.1} ERR [msg_load advvers2/8.3.1 $err_path'advvers@2.1' [err_reqlo advvers@2.1]]
 setenv_loaded_module [list advvers@2.1] [list $mp/advvers@2.1]
-testouterr_cmd_re sh {load --auto advvers2@8.3.1} ERR [msg_load advvers2/8.3.1 $err_path'advvers@2.1' [err_prereq advvers2/8.3.1 advvers@2.1]]
+testouterr_cmd_re sh {load --auto advvers2@8.3.1} ERR [msg_load advvers2/8.3.1 $err_path'advvers@2.1' [err_reqlo advvers@2.1]]
 set ans [list]
 lappend ans [list setpath LOADEDMODULES advvers@2.1:advvers2/8.3.2]
 lappend ans [list setpath _LMFILES_ $mp/advvers@2.1:$mp/advvers2/8.3.2]
@@ -693,7 +693,7 @@ if {![is_config_locked implicit_default]} {
     testouterr_cmd_re sh {load --auto advvers2@8.4.2} ERR [msg_load advvers2/8.4.2 [err_conflict advvers2/8.4.2 extdfl @1.3]]
     unsetenv_loaded_module
 
-    testouterr_cmd_re sh {load --auto advvers2@8.4.1} ERR [msg_load advvers2/8.4.1 "$err_nodefault'extdfl @1.4'" [err_prereq advvers2/8.4.1 "extdfl @1.4"]]
+    testouterr_cmd_re sh {load --auto advvers2@8.4.1} ERR [msg_load advvers2/8.4.1 "$err_nodefault'extdfl @1.4'" [err_reqlo "extdfl @1.4"]]
     setenv_var MODULES_IMPLICIT_DEFAULT 1
 }
 unsetenv_loaded_module
diff --git a/testsuite/modules.70-maint/271-adv_version_spec-in.exp b/testsuite/modules.70-maint/271-adv_version_spec-in.exp
index e6624bac4..cbfe58e80 100644
--- a/testsuite/modules.70-maint/271-adv_version_spec-in.exp
+++ b/testsuite/modules.70-maint/271-adv_version_spec-in.exp
@@ -764,7 +764,7 @@ testouterr_cmd_re sh {load advvers5@7.0} $ans {}
 unsetenv_loaded_module
 
 # test unknown module
-testouterr_cmd sh {load --auto advvers5@8.1.1} ERR [msg_load advvers5/8.1.1 $err_path'unknown@1.3.1,1.4.5' [err_prereq advvers5/8.1.1 unknown@1.3.1,1.4.5]]
+testouterr_cmd sh {load --auto advvers5@8.1.1} ERR [msg_load advvers5/8.1.1 $err_path'unknown@1.3.1,1.4.5' [err_reqlo unknown@1.3.1,1.4.5]]
 set ans [list]
 lappend ans [list setpath LOADEDMODULES advvers5/8.1.2]
 lappend ans [list setpath _LMFILES_ $mp/advvers5/8.1.2]
@@ -781,9 +781,9 @@ testouterr_cmd sh {load --auto advvers5@8.2.2} ERR [msg_load advvers5/8.2.2 [msg
 unsetenv_loaded_module
 
 # test mod@vers where a modulefile mod@vers exist
-testouterr_cmd_re sh {load --auto advvers5@8.3.1} ERR [msg_load advvers5/8.3.1 $err_path'advvers@2.1,2.2' [err_prereq advvers5/8.3.1 advvers@2.1,2.2]]
+testouterr_cmd_re sh {load --auto advvers5@8.3.1} ERR [msg_load advvers5/8.3.1 $err_path'advvers@2.1,2.2' [err_reqlo advvers@2.1,2.2]]
 setenv_loaded_module [list advvers@2.1] [list $mp/advvers@2.1]
-testouterr_cmd_re sh {load --auto advvers5@8.3.1} ERR [msg_load advvers5/8.3.1 $err_path'advvers@2.1,2.2' [err_prereq advvers5/8.3.1 advvers@2.1,2.2]]
+testouterr_cmd_re sh {load --auto advvers5@8.3.1} ERR [msg_load advvers5/8.3.1 $err_path'advvers@2.1,2.2' [err_reqlo advvers@2.1,2.2]]
 set ans [list]
 lappend ans [list setpath LOADEDMODULES advvers@2.1:advvers5/8.3.2]
 lappend ans [list setpath _LMFILES_ $mp/advvers@2.1:$mp/advvers5/8.3.2]
@@ -816,7 +816,7 @@ if {![is_config_locked implicit_default]} {
     testouterr_cmd_re sh {load --auto advvers5@8.4.2} ERR [msg_load advvers5/8.4.2 [err_conflict advvers5/8.4.2 extdfl @1.3,2]]
     unsetenv_loaded_module
 
-    testouterr_cmd_re sh {load --auto advvers5@8.4.1} ERR [msg_load advvers5/8.4.1 "$err_nodefault'extdfl @1.4,1.2'" [err_prereq advvers5/8.4.1 "extdfl @1.4,1.2"]]
+    testouterr_cmd_re sh {load --auto advvers5@8.4.1} ERR [msg_load advvers5/8.4.1 "$err_nodefault'extdfl @1.4,1.2'" [err_reqlo "extdfl @1.4,1.2"]]
     setenv_var MODULES_IMPLICIT_DEFAULT 1
 }
 unsetenv_loaded_module
diff --git a/testsuite/modules.70-maint/272-adv_version_spec-range.exp b/testsuite/modules.70-maint/272-adv_version_spec-range.exp
index 2e97d9cf0..326531dbc 100644
--- a/testsuite/modules.70-maint/272-adv_version_spec-range.exp
+++ b/testsuite/modules.70-maint/272-adv_version_spec-range.exp
@@ -883,7 +883,7 @@ testouterr_cmd_re sh {load advvers7@7.0} $ans {}
 unsetenv_loaded_module
 
 # test unknown module
-testouterr_cmd sh {load --auto advvers7@8.1.1} ERR [msg_load advvers7/8.1.1 $err_path'unknown@:1.4.5' [err_prereq advvers7/8.1.1 unknown@:1.4.5]]
+testouterr_cmd sh {load --auto advvers7@8.1.1} ERR [msg_load advvers7/8.1.1 $err_path'unknown@:1.4.5' [err_reqlo unknown@:1.4.5]]
 set ans [list]
 lappend ans [list setpath LOADEDMODULES advvers7/8.1.2]
 lappend ans [list setpath _LMFILES_ $mp/advvers7/8.1.2]
@@ -900,9 +900,9 @@ testouterr_cmd sh {load --auto advvers7@8.2.2} ERR [msg_load advvers7/8.2.2 [msg
 unsetenv_loaded_module
 
 # test mod@vers where a modulefile mod@vers exist
-testouterr_cmd_re sh {load --auto advvers7@8.3.1} ERR [msg_load advvers7/8.3.1 $err_path'advvers@2.1:' [err_prereq advvers7/8.3.1 advvers@2.1:]]
+testouterr_cmd_re sh {load --auto advvers7@8.3.1} ERR [msg_load advvers7/8.3.1 $err_path'advvers@2.1:' [err_reqlo advvers@2.1:]]
 setenv_loaded_module [list advvers@2.1] [list $mp/advvers@2.1]
-testouterr_cmd_re sh {load --auto advvers7@8.3.1} ERR [msg_load advvers7/8.3.1 $err_path'advvers@2.1:' [err_prereq advvers7/8.3.1 advvers@2.1:]]
+testouterr_cmd_re sh {load --auto advvers7@8.3.1} ERR [msg_load advvers7/8.3.1 $err_path'advvers@2.1:' [err_reqlo advvers@2.1:]]
 set ans [list]
 lappend ans [list setpath LOADEDMODULES advvers@2.1:advvers7/8.3.2]
 lappend ans [list setpath _LMFILES_ $mp/advvers@2.1:$mp/advvers7/8.3.2]
@@ -935,7 +935,7 @@ if {![is_config_locked implicit_default]} {
     testouterr_cmd_re sh {load --auto advvers7@8.4.2} ERR [msg_load advvers7/8.4.2 [err_conflict advvers7/8.4.2 extdfl @1.3:2]]
     unsetenv_loaded_module
 
-    testouterr_cmd_re sh {load --auto advvers7@8.4.1} ERR [msg_load advvers7/8.4.1 "$err_nodefault'extdfl @1.4:1.5'" [err_prereq advvers7/8.4.1 "extdfl @1.4:1.5"]]
+    testouterr_cmd_re sh {load --auto advvers7@8.4.1} ERR [msg_load advvers7/8.4.1 "$err_nodefault'extdfl @1.4:1.5'" [err_reqlo "extdfl @1.4:1.5"]]
     setenv_var MODULES_IMPLICIT_DEFAULT 1
 }
 unsetenv_loaded_module
diff --git a/version.inc.in b/version.inc.in
index 1c655f839..10fce9d7a 100644
--- a/version.inc.in
+++ b/version.inc.in
@@ -1,7 +1,7 @@
 # Release definitions shared across the Makefiles of this project
 # run make to generate version.inc
 
-MODULES_RELEASE := 4.5.1
+MODULES_RELEASE := 4.5.3
 MODULES_BUILD_HASH := $Format:%h$
 MODULES_BUILD_REFS := $Format:%D$
 MODULES_BUILD_FDATE := $Format:%ci$