diff --git a/common/foundry_install.py b/common/foundry_install.py
index b551b40..34e3a46 100755
--- a/common/foundry_install.py
+++ b/common/foundry_install.py
@@ -251,8 +251,6 @@
 #   %l :  substitute the library name
 #   %% :  substitute the percent character verbatim
 
-from packaging import version
-
 #----------------------------------------------------------------------------
 #----------------------------------------------------------------------------
 
@@ -307,6 +305,64 @@
 #----------------------------------------------------------------------------
 #----------------------------------------------------------------------------
 
+def parse_version_number(vstring):
+    verex1 = re.compile('[^0-9]*([0-9]+)')
+    verex2 = re.compile('[^0-9]*([0-9]+)[^0-9]*([0-9]+)')
+    verex3 = re.compile('[^0-9]*([0-9]+)[^0-9]*([0-9]+)[^0-9]*([0-9]+)')
+    major = 0
+    minor = 0
+    revision = 0
+    try:
+        vnums = verex3.match(vstring)
+    except:
+        try:
+            vnums = verex2.match(vstring)
+        except:
+            try:
+                vnums = verex1.match(vstring)
+            except:
+                print('Error:  String ' + vstring + ' cannot be parsed as '
+				+ 'a version number.')
+            else:
+                major = int(vnums.group(1))
+        else:
+            major = int(vnums.group(1))
+            minor = int(vnums.group(2))
+    else:
+        major = int(vnums.group(1))
+        minor = int(vnums.group(2))
+        revision = int(vnums.group(3))
+
+    return [major, minor, revision]
+
+#----------------------------------------------------------------------------
+#----------------------------------------------------------------------------
+
+def version_compare(vlist1, vlist2):
+    major1 = vlist1[0]
+    major2 = vlist2[0]
+    minor1 = vlist1[1]
+    minor2 = vlist2[1]
+    revision1 = vlist1[2]
+    revision2 = vlist2[2]
+    if major1 > major2:
+        return True
+    elif major1 < major2:
+        return False
+    else:
+        if minor1 > minor2:
+            return True
+        elif minor1 < minor2:
+            return False
+        else:
+            if revision1 > revision2:
+                return True
+            else:
+                return False
+
+#----------------------------------------------------------------------------
+#----------------------------------------------------------------------------
+
 def substitute(pathname, library):
     if library:
         # Do %l substitution
@@ -324,7 +380,8 @@
         else:
             for vlib in vlibs[1:]:
                 vtest = vlib[len(vglob)-1:]
-                if version.parse(vtest) > version.parse(vstr):
+                if version_compare(parse_version_number(vtest),
+				parse_version_number(vstr)):
                     vstr = vtest
             newpathname = re.sub('%v', vstr, newpathname)
 
diff --git a/gf180mcu/gf180mcu.json b/gf180mcu/gf180mcu.json
index 0829555..d6d30a6 100644
--- a/gf180mcu/gf180mcu.json
+++ b/gf180mcu/gf180mcu.json
@@ -89,8 +89,8 @@
         "magic": "MAGIC_COMMIT"
     },
     "reference": {
-        "open_pdks": "8c312fd9be7c9a9a2821c0821d1421c00e13d139",
-        "magic": "b7942cffe6de3bac78bef3ee745097ecd72c689f",
+        "open_pdks": "c10a581884a4373c1a48b18ea3fc02c19d8d5c88",
+        "magic": "4445663cb1b2de1eb9818cfe89f60ed7659335f3",
         "gf180mcu_pdk": "a897aa30369d3bcec87d9d50ce9b01f320f854ef",
         "gf180mcu_fd_pr": "a11222d681f2134ab28e97f97b9b99b6af188f88",
         "gf180mcu_fd_pv": "e9410df04da5b64a1053aa6e5180dc144b8a12a2",
diff --git a/sky130/sky130.json b/sky130/sky130.json
index b69d8f9..4800903 100644
--- a/sky130/sky130.json
+++ b/sky130/sky130.json
@@ -94,10 +94,10 @@
         "magic": "MAGIC_COMMIT"
     },
     "reference": {
-        "open_pdks": "a67574f86dc944797c17229e94fd8fc9d6fbf949",
-        "magic": "dc87a8c6936e89a557a3a84e6acc4c8321b9079e",
-        "sky130_fd_pr": "514d4dc1d67632015e1de2cb7de60e21653cd94c",
-        "sky130_fd_io": "d3b662d017ce4fb5d4e3c3922ac81f744111e010",
+        "open_pdks": "c10a581884a4373c1a48b18ea3fc02c19d8d5c88",
+        "magic": "4445663cb1b2de1eb9818cfe89f60ed7659335f3",
+        "sky130_fd_pr": "1232782c1b9fab3aacda74d67ce7c92bf7da8105",
+        "sky130_fd_io": "b9c10d039816c4026f9a10cf8a200b9b5caa1b63",
         "sky130_fd_sc_hs": "9a855e97aa75f8a14be7eadc365c28d50045d5fc",
         "sky130_fd_sc_ms": "26d0047c0e2dbe28fe4950f171411f6e8b3d0564",
         "sky130_fd_sc_ls": "8e7040bfc58a17386e3d900c0e3b9c9163545c4a",