Only 3.10.x branch of ZODB3 is supported

Next version is actually a metapackage depending on:
  persistent 4.0
  BTrees 4.0
  ZODB 4.0
  ZEO 4.0

Note that version '123dev' is considered lower than '123'

setup.py

@@ -26,7 +26,7 @@ if not os.path.exists('mock.py'):
 
 extras_require = {
     'admin': [],
-    'client': ['ZODB3>=3.10'],
+    'client': ['ZODB3>=3.10', 'ZODB3<3.11dev'],
     'ctl': [],
     'master': [],
     'storage-sqlite': [],