diff --git a/HISTORY.rst b/HISTORY.rst
index c1668e51..9c1116ec 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -8,6 +8,11 @@ PlatformIO Core 5
 
 **A professional collaborative platform for embedded development**
 
+5.0.2 (2020-09-??)
+~~~~~~~~~~~~~~~~~~
+
+- Fixed an issue with "KeyError: 'versions'" when dependency does not exist in the registry (`issue #3666 <https://github.com/platformio/platformio-core/issues/3666>`_)
+
 5.0.1 (2020-09-10)
 ~~~~~~~~~~~~~~~~~~
 
diff --git a/platformio/__init__.py b/platformio/__init__.py
index 145ad0cf..7159c500 100644
--- a/platformio/__init__.py
+++ b/platformio/__init__.py
@@ -14,7 +14,7 @@
 
 import sys
 
-VERSION = (5, 0, 1)
+VERSION = (5, 0, "2a1")
 __version__ = ".".join([str(s) for s in VERSION])
 
 __title__ = "platformio"
diff --git a/platformio/clients/http.py b/platformio/clients/http.py
index 4d59bcaa..1e22ca97 100644
--- a/platformio/clients/http.py
+++ b/platformio/clients/http.py
@@ -133,9 +133,7 @@ class HTTPClient(object):
     def fetch_json_data(self, method, path, **kwargs):
         cache_valid = kwargs.pop("cache_valid") if "cache_valid" in kwargs else None
         if not cache_valid:
-            return self.raise_error_from_response(
-                self.send_request(method, path, **kwargs)
-            )
+            return self._parse_json_response(self.send_request(method, path, **kwargs))
         cache_key = ContentCache.key_from_args(
             method, path, kwargs.get("params"), kwargs.get("data")
         )
@@ -144,11 +142,12 @@ class HTTPClient(object):
             if result is not None:
                 return json.loads(result)
             response = self.send_request(method, path, **kwargs)
+            data = self._parse_json_response(response)
             cc.set(cache_key, response.text, cache_valid)
-            return self.raise_error_from_response(response)
+            return data
 
     @staticmethod
-    def raise_error_from_response(response, expected_codes=(200, 201, 202)):
+    def _parse_json_response(response, expected_codes=(200, 201, 202)):
         if response.status_code in expected_codes:
             try:
                 return response.json()