diff --git a/.circleci/config.yml b/.circleci/config.yml
index 31a4f50c..4603c7bb 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -21,38 +21,38 @@ workflows:
           #baselibs_version: *baselibs_version
           repo: GEOSgcm
           checkout_fixture: true
-          # V12 code uses a special branch for now.
-          fixture_branch: feature/sdrabenh/gcm_v12
-          # We comment out this as it will "undo" the fixture_branch
-          #mepodevelop: true
-          persist_workspace: true # Needs to be true to run fv3/gcm experiment, costs extra
+          mepodevelop: false
+          fixture_branch: release/MAPL-v3
+          persist_workspace: false # Needs to be true to run fv3/gcm experiment, costs extra
 
-      # Run AMIP GCM (1 hour, no ExtData)
-      - ci/run_gcm:
-          name: run-GCM-on-<< matrix.compiler >>
-          context:
-            - docker-hub-creds
-          matrix:
-            parameters:
-              compiler: [gfortran, ifort]
-          requires:
-            - build-GEOSgcm-on-<< matrix.compiler >>
-          repo: GEOSgcm
-          #baselibs_version: *baselibs_version
-          #bcs_version: *bcs_version
-
-      # Run Coupled GCM (1 hour, no ExtData)
-      - ci/run_gcm:
-          name: run-coupled-GCM-on-<< matrix.compiler >>
-          context:
-            - docker-hub-creds
-          matrix:
-            parameters:
-              compiler: [ifort]
-          requires:
-            - build-GEOSgcm-on-<< matrix.compiler >>
-          repo: GEOSgcm
-          #baselibs_version: *baselibs_version
-          #bcs_version: *bcs_version
-          gcm_ocean_type: MOM6
-          change_layout: false
+      ######################################################
+      # # Run AMIP GCM (1 hour, no ExtData)                #
+      # - ci/run_gcm:                                      #
+      #     name: run-GCM-on-<< matrix.compiler >>         #
+      #     context:                                       #
+      #       - docker-hub-creds                           #
+      #     matrix:                                        #
+      #       parameters:                                  #
+      #         compiler: [gfortran, ifort]                #
+      #     requires:                                      #
+      #       - build-GEOSgcm-on-<< matrix.compiler >>     #
+      #     repo: GEOSgcm                                  #
+      #     #baselibs_version: *baselibs_version           #
+      #     #bcs_version: *bcs_version                     #
+      #                                                    #
+      # # Run Coupled GCM (1 hour, no ExtData)             #
+      # - ci/run_gcm:                                      #
+      #     name: run-coupled-GCM-on-<< matrix.compiler >> #
+      #     context:                                       #
+      #       - docker-hub-creds                           #
+      #     matrix:                                        #
+      #       parameters:                                  #
+      #         compiler: [ifort]                          #
+      #     requires:                                      #
+      #       - build-GEOSgcm-on-<< matrix.compiler >>     #
+      #     repo: GEOSgcm                                  #
+      #     #baselibs_version: *baselibs_version           #
+      #     #bcs_version: *bcs_version                     #
+      #     gcm_ocean_type: MOM6                           #
+      #     change_layout: false                           #
+      ######################################################
diff --git a/.github/workflows/workflow.yml b/.github/workflows/workflow.yml
index 7696a7d1..d3b16061 100644
--- a/.github/workflows/workflow.yml
+++ b/.github/workflows/workflow.yml
@@ -26,7 +26,8 @@ jobs:
       compiler: ${{ matrix.compiler }}
       cmake-build-type: ${{ matrix.build-type }}
       fixture-repo: GEOS-ESM/GEOSgcm
-      fixture-ref: feature/sdrabenh/gcm_v12
+      fixture-ref: release/MAPL-v3
+      run-mepo-develop: false
 
   spack_build:
     uses: GEOS-ESM/CI-workflows/.github/workflows/spack_gcc_build.yml@project/geosgcm
@@ -35,5 +36,10 @@ jobs:
       BUILDCACHE_TOKEN: ${{ secrets.BUILDCACHE_TOKEN }}
     with:
       fixture-repo: GEOS-ESM/GEOSgcm
-      fixture-ref: feature/sdrabenh/gcm_v12
+      fixture-ref: release/MAPL-v3
+      run-mepo-develop: false
+      patch-esmf: true
+      # There is some weird issue with spack builds and the install step with
+      # MAPL 3. For now, turn off as we don't need to *run* GEOS.
+      run-install: false
 
diff --git a/GEOS_Shared/CMakeLists.txt b/GEOS_Shared/CMakeLists.txt
index e5cb6a83..00550c2b 100644
--- a/GEOS_Shared/CMakeLists.txt
+++ b/GEOS_Shared/CMakeLists.txt
@@ -8,7 +8,7 @@ set (srcs
   getco2.F90 atmOceanIntLayer.F90
   )
 
-esma_add_library(${this} SRCS ${srcs} DEPENDENCIES MAPL ESMF::ESMF NetCDF::NetCDF_Fortran)
+esma_add_library(${this} SRCS ${srcs} DEPENDENCIES MAPL2 MAPL ESMF::ESMF NetCDF::NetCDF_Fortran)
 
 # special cases
 set_source_files_properties(sphere.F PROPERTIES COMPILE_FLAGS "${FREAL8}")
diff --git a/GEOS_Shared/G3_MPI_Util_Mod.F90 b/GEOS_Shared/G3_MPI_Util_Mod.F90
index a14d0b59..ecafd54b 100644
--- a/GEOS_Shared/G3_MPI_Util_Mod.F90
+++ b/GEOS_Shared/G3_MPI_Util_Mod.F90
@@ -1,7 +1,7 @@
 #include "unused_dummy.H"
       module G3_MPI_Util_Mod
 
-      use MAPL
+      use MAPL2
       implicit none
 
 ! Define Lattice
diff --git a/GEOS_Shared/GEOS_TopoGet.F90 b/GEOS_Shared/GEOS_TopoGet.F90
index 6dd62882..4f92d41e 100644
--- a/GEOS_Shared/GEOS_TopoGet.F90
+++ b/GEOS_Shared/GEOS_TopoGet.F90
@@ -14,7 +14,7 @@ module GEOS_TopoGetMod
 ! !USES:
 
   use ESMF
-  use MAPL
+  use MAPL2
   
   implicit none
   private
diff --git a/GEOS_Shared/OVP.F90 b/GEOS_Shared/OVP.F90
index 61c2bbc8..d4ad0b73 100644
--- a/GEOS_Shared/OVP.F90
+++ b/GEOS_Shared/OVP.F90
@@ -13,7 +13,7 @@ module OVP
 ! !USES:
 
   use ESMF
-  use MAPL
+  use MAPL2
   
   implicit none
   private
diff --git a/GEOS_Shared/atmOceanIntLayer.F90 b/GEOS_Shared/atmOceanIntLayer.F90
index c283b82b..74b6ed69 100644
--- a/GEOS_Shared/atmOceanIntLayer.F90
+++ b/GEOS_Shared/atmOceanIntLayer.F90
@@ -2,7 +2,7 @@ module atmOcnIntlayer
 
 ! !USES:
 
-use MAPL
+use MAPL2
 use GEOS_UtilsMod, only: GEOS_QSAT, GEOS_DQSAT
 
 implicit none
diff --git a/GEOS_Shared/condense.F90 b/GEOS_Shared/condense.F90
index 17323b4b..6ba68412 100644
--- a/GEOS_Shared/condense.F90
+++ b/GEOS_Shared/condense.F90
@@ -31,7 +31,7 @@ subroutine condensation(T,P,Qv,Ql,SuperSat)
 
   subroutine Iterate(TT,PP,QQ,QC,SuperSat)
 
-    use MAPL, only : QSAT=>MAPL_EQSAT, MAPL_ALHL, MAPL_CP, MAPL_AIRMW, MAPL_RUNIV, MAPL_RDRY, MAPL_RGAS, MAPL_CP
+    use MAPL2, only : QSAT=>MAPL_EQSAT, MAPL_ALHL, MAPL_CP, MAPL_AIRMW, MAPL_RUNIV, MAPL_RDRY, MAPL_RGAS, MAPL_CP
 
     implicit none
 
diff --git a/GEOS_Shared/surfacelayer.F90 b/GEOS_Shared/surfacelayer.F90
index 520dbe0b..94214ca1 100644
--- a/GEOS_Shared/surfacelayer.F90
+++ b/GEOS_Shared/surfacelayer.F90
@@ -5,7 +5,7 @@ module sfclayer
 
 ! !USES:
 
-use MAPL
+use MAPL2
 use DragCoefficientsMod
 
 implicit none
diff --git a/GEOS_Shared/tropovars.F90 b/GEOS_Shared/tropovars.F90
index 1c37e6a8..e589d7f4 100644
--- a/GEOS_Shared/tropovars.F90
+++ b/GEOS_Shared/tropovars.F90
@@ -62,7 +62,7 @@ subroutine tropovars (im,jm,lm,ple,pl,                               &
 !
 !********************************************************************
 
-  use MAPL
+  use MAPL2
 
       implicit none
 
diff --git a/GEOS_Shared/windfix.F90 b/GEOS_Shared/windfix.F90
index 55ade693..34d3cbac 100644
--- a/GEOS_Shared/windfix.F90
+++ b/GEOS_Shared/windfix.F90
@@ -6,7 +6,7 @@ subroutine windfix ( ua,va,plea,                            &
                            vintdiva,vintdivb,vintdivc )
 
       use ESMF
-      use MAPL
+      use MAPL2
 
       implicit none