diff --git a/CHANGELOG.md b/CHANGELOG.md
index 38bbef5..941fdde 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- NCCS has retired SLES12, so the conditions on SLES12 and SLES15 are removed
 - Updated subroutine read_obs_sm_ASCAT_EUMET() to work with both original and revised file name templates. 
 - Updated subroutines read_obs_sm_ASCAT_EUMET(), read_obs_SMAP_halforbit_Tb(), read_obs_SMOS() and read_obs_MODIS_SCF() with hardcoded time ranges for when observations are available and should be read.
 - Revised variable names (SHORT_NAME) and descriptions (LONG_NAME) to match M21C file specs.
diff --git a/GEOSldas_App/ldas_setup b/GEOSldas_App/ldas_setup
index dfbe28e..30649d0 100755
--- a/GEOSldas_App/ldas_setup
+++ b/GEOSldas_App/ldas_setup
@@ -51,12 +51,6 @@ class LDASsetup:
             'MINLON','MAXLON','MINLAT','MAXLAT','EXCLUDE_FILE','INCLUDE_FILE','MWRTM_PATH','GRIDNAME',
             'ADAS_EXPDIR', 'BCS_RESOLUTION' ]
 
-        # if built on sles15, BUILT_ON_SLES15 is "TRUE", else empty ""
-        BUILT_ON_SLES15 = "@BUILT_ON_SLES15@"
-        if BUILT_ON_SLES15 == "TRUE":
-          self.BUILT_ON_SLES15 = True
-        else:
-          self.BUILT_ON_SLES15 = False
 
         self.GEOS_SITE       = "@GEOS_SITE@"
 
@@ -705,10 +699,7 @@ class LDASsetup:
         print ('\nCorrect the tile file if it is an old EASE tile format... \n')
         EASEtile=self.bcsdir+'/MAPL_'+short_tile
         cmd = self.bindir + '/preprocess_ldas.x correctease  '+ tile + ' '+ EASEtile
-        if self.BUILT_ON_SLES15 :
-          print ("Executables were built on SLES15 and must be run on SLES15:   " + cmd)
-        else:
-          print ("cmd:   " + cmd)
+        print ("cmd:   " + cmd)
 
         sp.call(shlex.split(cmd))
 
@@ -1358,10 +1349,8 @@ class LDASsetup:
         constraint='cas'
         if self.GEOS_SITE == "NAS":
           constraint = 'cas_ait'
-        elif self.BUILT_ON_SLES15:
-          constraint = 'mil'
-        else:
-           assert int(self.rqdRmInp['ntasks-per-node']) <= 46, 'ntasks-per-node should be <=46 for cas'
+        elif self.GEOS_SITE == "NCCS":
+          constraint = '"[mil|cas]"'
 
         SBATCHQSUB = 'sbatch'
         if self.GEOS_SITE == 'NAS':
@@ -1393,7 +1382,6 @@ class LDASsetup:
                   MY_ADAS_EXPDIR     = self.adas_expdir,
                   MY_EXPDIR          = self.expdir,
                   DETECTED_MPI_STACK = DETECTED_MPI_STACK,
-                  BUILT_ON_SLES15    = str(self.BUILT_ON_SLES15).upper()
                   )
 
         with open('lenkf.j','wt') as fout :
diff --git a/GEOSldas_App/lenkf_j_template.py b/GEOSldas_App/lenkf_j_template.py
index 0182edb..45abc2e 100644
--- a/GEOSldas_App/lenkf_j_template.py
+++ b/GEOSldas_App/lenkf_j_template.py
@@ -87,12 +87,8 @@
 
 else if ( ${{MPI_STACK}} == "intelmpi" ) then
 
-    setenv BUILT_ON_SLES15 {BUILT_ON_SLES15}
-
-    if ( ${{BUILT_ON_SLES15}} == TRUE ) then
-        setenv I_MPI_FABRICS shm:ofi
-        setenv I_MPI_OFI_PROVIDER psm3
-    endif # BUILT_ON_SLES15
+    setenv I_MPI_FABRICS shm:ofi
+    setenv I_MPI_OFI_PROVIDER psm3
 
 endif # MPI_STACK