Discovered a handful of strings in python scripts that use
backslashes for regular expressions but do not prefix the string
with 'r'.  Although there was a concerted effort some time ago to
fix all the script, a handful of lines were missed.  Thanks to
Brad Minch for reporting the error!
diff --git a/VERSION b/VERSION
index d1e8534..2cc2aa0 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.0.539
+1.0.540
diff --git a/gf180mcu/custom/scripts/convert_sc_cdl.py b/gf180mcu/custom/scripts/convert_sc_cdl.py
index a03b225..26f3c7a 100755
--- a/gf180mcu/custom/scripts/convert_sc_cdl.py
+++ b/gf180mcu/custom/scripts/convert_sc_cdl.py
@@ -41,7 +41,7 @@
 	# 3) Uppercase diode "d" for consistency
         fixedline = re.sub('^d', 'D', fixedline)
 	# 4) Convert $m to M
-        fixedline = re.sub('\$m=', 'M=', fixedline, flags=re.IGNORECASE)
+        fixedline = re.sub(r'\$m=', 'M=', fixedline, flags=re.IGNORECASE)
 	# 5) Fix incorrect endcap (endcap does not have VNW VPW)
         fixedline = re.sub('endcap VDD VNW VPW', 'endcap VDD', fixedline, flags=re.IGNORECASE)
 	# 6) Fix incorrect diode properties in antenna cell (missing key)
diff --git a/gf180mcu/custom/scripts/convert_sram_cdl.py b/gf180mcu/custom/scripts/convert_sram_cdl.py
index b07c09b..ae1a8d7 100755
--- a/gf180mcu/custom/scripts/convert_sram_cdl.py
+++ b/gf180mcu/custom/scripts/convert_sram_cdl.py
@@ -36,10 +36,10 @@
         # 2) 5V transistor models --> change to 6V
         fixedline = re.sub('_05v0', '_06v0', fixedline, flags=re.IGNORECASE)
         # 3) Remove $X, $Y, $D, and $T parameters
-        fixedline = re.sub('\$X=-?[0-9]+', '', fixedline, flags=re.IGNORECASE)
-        fixedline = re.sub('\$Y=-?[0-9]+', '', fixedline, flags=re.IGNORECASE)
-        fixedline = re.sub('\$D=-?[0-9]+', '', fixedline, flags=re.IGNORECASE)
-        fixedline = re.sub('\$T=-?[0-9]+ -?[0-9]+ -?[0-9]+ -?[0-9]+', '',
+        fixedline = re.sub(r'\$X=-?[0-9]+', '', fixedline, flags=re.IGNORECASE)
+        fixedline = re.sub(r'\$Y=-?[0-9]+', '', fixedline, flags=re.IGNORECASE)
+        fixedline = re.sub(r'\$D=-?[0-9]+', '', fixedline, flags=re.IGNORECASE)
+        fixedline = re.sub(r'\$T=-?[0-9]+ -?[0-9]+ -?[0-9]+ -?[0-9]+', '',
 			fixedline, flags=re.IGNORECASE)
 
         if line != fixedline:
diff --git a/sky130/custom/scripts/rename_models.py b/sky130/custom/scripts/rename_models.py
index f95f5ba..002fafc 100755
--- a/sky130/custom/scripts/rename_models.py
+++ b/sky130/custom/scripts/rename_models.py
@@ -49,7 +49,7 @@
     for line in spilines:
 
         # Modify: Replace "../cells/<name>/" with "../../libs.ref/sky130_fd_pr/spice/"
-        fixedline = re.sub('\.\./cells/[^/]+/', '../../libs.ref/' + libpath, line)
+        fixedline = re.sub(r'\.\./cells/[^/]+/', '../../libs.ref/' + libpath, line)
         fixedlines.append(fixedline)
         if fixedline != line:
             modified = True