diff --git a/compiler/characterizer/stimuli.py b/compiler/characterizer/stimuli.py
index 297d9f37..578bb2c2 100644
--- a/compiler/characterizer/stimuli.py
+++ b/compiler/characterizer/stimuli.py
@@ -286,6 +286,7 @@ class stimuli():
                                                          OPTS.openram_temp)
             valid_retcode=0
         else:
+            # ngspice 27+ supports threading with "set num_threads=4" in the stimulus file or a .spiceinit 
             cmd = "{0} -b -o {2}timing.lis {1}".format(OPTS.spice_exe,
                                                        temp_stim,
                                                        OPTS.openram_temp)
diff --git a/technology/scn3me_subm/models/ff/nmos.sp b/technology/scn3me_subm/models/ff/nmos.sp
index 70ffd267..278dfc57 100644
--- a/technology/scn3me_subm/models/ff/nmos.sp
+++ b/technology/scn3me_subm/models/ff/nmos.sp
@@ -6,5 +6,5 @@
 *********************************************
 
 .MODEL n NMOS (LEVEL=49 VTHO=0.669845 KP=113.7771E-6
-+ NSUB=6E16 U0=461 K1=0.5705 TOX=13.9n)
++ NSUB=6E16 U0=461 K1=0.5705 TOX=13.9n VERSION=3.3.0)
 
diff --git a/technology/scn3me_subm/models/ff/pmos.sp b/technology/scn3me_subm/models/ff/pmos.sp
index ee0d9691..86ad3cf1 100644
--- a/technology/scn3me_subm/models/ff/pmos.sp
+++ b/technology/scn3me_subm/models/ff/pmos.sp
@@ -6,4 +6,4 @@
 *********************************************
 
 .MODEL p PMOS (LEVEL=49 VTHO=-0.322431 KP=366.0244-6
-+ NSUB=6E16 U0=212 K1=0.0821 TOX=13.9n)
++ NSUB=6E16 U0=212 K1=0.0821 TOX=13.9n VERSION=3.3.0)
diff --git a/technology/scn3me_subm/models/nom/nmos.sp b/technology/scn3me_subm/models/nom/nmos.sp
index d83289e8..150788b4 100644
--- a/technology/scn3me_subm/models/nom/nmos.sp
+++ b/technology/scn3me_subm/models/nom/nmos.sp
@@ -6,4 +6,4 @@
 *********************************************
 
 .MODEL n NMOS (LEVEL=49 VTHO=0.669845 KP=113.7771E-6
-+ NSUB=6E16 U0=458 K1=0.5705 TOX=13.9n)
++ NSUB=6E16 U0=458 K1=0.5705 TOX=13.9n VERSION=3.3.0)
diff --git a/technology/scn3me_subm/models/nom/pmos.sp b/technology/scn3me_subm/models/nom/pmos.sp
index ee0d9691..4cf58290 100644
--- a/technology/scn3me_subm/models/nom/pmos.sp
+++ b/technology/scn3me_subm/models/nom/pmos.sp
@@ -6,4 +6,4 @@
 *********************************************
 
 .MODEL p PMOS (LEVEL=49 VTHO=-0.322431 KP=366.0244-6
-+ NSUB=6E16 U0=212 K1=0.0821 TOX=13.9n)
++ NSUB=6E16 U0=212 K1=0.0821 TOX=13.9n  VERSION=3.3.0)
diff --git a/technology/scn3me_subm/models/ss/nmos.sp b/technology/scn3me_subm/models/ss/nmos.sp
index 667667cd..1728b331 100644
--- a/technology/scn3me_subm/models/ss/nmos.sp
+++ b/technology/scn3me_subm/models/ss/nmos.sp
@@ -6,5 +6,5 @@
 *********************************************
 
 .MODEL n NMOS (LEVEL=49 VTHO=0.669845 KP=113.7771E-6
-+ NSUB=6E16 U0=460 K1=0.5705 TOX=13.9n)
++ NSUB=6E16 U0=460 K1=0.5705 TOX=13.9n VERSION=3.3.0)
 
diff --git a/technology/scn3me_subm/models/ss/pmos.sp b/technology/scn3me_subm/models/ss/pmos.sp
index ee0d9691..86ad3cf1 100644
--- a/technology/scn3me_subm/models/ss/pmos.sp
+++ b/technology/scn3me_subm/models/ss/pmos.sp
@@ -6,4 +6,4 @@
 *********************************************
 
 .MODEL p PMOS (LEVEL=49 VTHO=-0.322431 KP=366.0244-6
-+ NSUB=6E16 U0=212 K1=0.0821 TOX=13.9n)
++ NSUB=6E16 U0=212 K1=0.0821 TOX=13.9n VERSION=3.3.0)