diff --git a/PhysSys/cmt/requirements b/PhysSys/cmt/requirements
index 016453f33bbe450b0674e86d60724530461a67d1..8c08ed5306ce815979b7e10c42205459a95c594a 100755
--- a/PhysSys/cmt/requirements
+++ b/PhysSys/cmt/requirements
@@ -1,5 +1,5 @@
 package PhysSys
-version           v12r5g2
+version           v12r5g3
 
 branches doc cmt
 
diff --git a/ReleaseNotes/v12r5g3.md b/ReleaseNotes/v12r5g3.md
new file mode 100644
index 0000000000000000000000000000000000000000..2fc0f3c1efacd9e8d83b7f15ef9ab359664935fe
--- /dev/null
+++ b/ReleaseNotes/v12r5g3.md
@@ -0,0 +1,37 @@
+2024-12-11 Phys v12r5g3
+===
+
+This version uses
+Rec [v11r5g3](../../../../Rec/-/tags/v11r5g3),
+LHCb [v32r4g3](../../../../LHCb/-/tags/v32r4g3),
+Gaudi [v22r5](../../../../Gaudi/-/tags/v22r5) and
+LCG [61b](http://lcginfo.cern.ch/release/61b/) with ROOT 5.30.04.
+
+This version is released on `hlt2011-patches` branch. This branch is intended *only* for technical fixes to support emulation of the 2011 HLT in simulation workflows. Builds with gcc43 on slc5.
+Built relative to Phys [v12r5g2](../-/tags/v12r5g2), with the following changes:
+
+### New features ~"new feature"
+
+- Add copyright statement and copyright check, !852 (@cattanem)
+- Add release notes template, !848 (@cattanem)
+
+
+### Fixes ~"bug fix" ~workaround
+
+- Remove OPTIONS "-U__MINGW32__" from gaudi_add_dictionary directive, !717 (@cattanem)
+
+
+### Code cleanups and changes to tests ~modernisation ~cleanup ~testing
+
+- ~Build | Remove ifdefs and link options for OSX and ICC, not supported on this branch, !842 (@cattanem)
+- Remove CVS keywords, !846 (@cattanem)
+- Replace savannah bugs by corresponding JIRA tasks (@pkoppenb), !795 (@cattanem)
+
+
+### Documentation ~Documentation
+
+- Add copyright statement and copyright check, !852 (@cattanem)
+- Add release notes template, !848 (@cattanem)
+- Remove CVS keywords, !846 (@cattanem)
+- Replace savannah bugs by corresponding JIRA tasks (@pkoppenb), !795 (@cattanem)
+
diff --git a/cmt/project.cmt b/cmt/project.cmt
index 0c1c6030de81af4757d44807dcbb56bba2d0039f..7f429d37e2c8bb2cb783f7baecbc6725159f9cbf 100755
--- a/cmt/project.cmt
+++ b/cmt/project.cmt
@@ -1,6 +1,6 @@
 project PHYS
 
-use REC	REC_v11r5g2
+use REC	REC_v11r5g3
 
 container      PhysSys
 build_strategy	with_installarea