diff --git a/src/Mod/AddonManager/AddonManager.py b/src/Mod/AddonManager/AddonManager.py
index cfae6a6d6127..d0bf50efc59b 100644
--- a/src/Mod/AddonManager/AddonManager.py
+++ b/src/Mod/AddonManager/AddonManager.py
@@ -258,7 +258,13 @@ def launch(self) -> None:
         if last_cache_update_string == "never":
             self.update_cache = True
         elif days_between_updates > 0:
-            last_cache_update = date.fromisoformat(last_cache_update_string)
+            if hasattr(date, "fromisoformat"):
+                last_cache_update = date.fromisoformat(last_cache_update_string)
+            else:
+                # Python 3.6 and earlier don't have date.fromisoformat
+                date_re = re.compile("([0-9]{4})-?(1[0-2]|0[1-9])-?(3[01]|0[1-9]|[12][0-9])")
+                matches = date_re.match (last_cache_update_string)
+                last_cache_update = date(int(matches.group(1)),int(matches.group(2)),int(matches.group(3)))
             delta_update = timedelta(days=days_between_updates)
             if date.today() >= last_cache_update + delta_update:
                 self.update_cache = True