I tried with beta 42 and the latest AnkiConnect from 2018-06-24. This is the only addon installed. I don't call AnkiConnect directly but from within an emacs package that's called anki-editor. This package allows to send/push notes to AnkiConnect. When I run the "push" command in this package I get the following error message in Anki.
This emacs package works fine with AnkiConnect in 2.0.52. So I assume that the problem is not with this emacs-package? I don't know about the internals of emacs/elisp so I can't tell you what exactly is sent to AnkiConnect. Nevertheless I decided to post because this error message might still be useful for you ? If you feel that a novice like me can help with further information just give me instructions on what to do.
Anyway thanks for your great software.
Debug info:
Anki 2.1.0beta42 Python 3.6.2 Qt 5.9.2 PyQt 5.9
Platform: Linux
Flags: frz=True ao=True sv=1
Caught exception:
File "/the/path/to/profile/addons21/2055492159/__init__.py", line 293, in advance
self.server.advance()
File "/the/path/to/profile/addons21/2055492159/__init__.py", line 204, in advance
self.advanceClients()
File "/the/path/to/profile/addons21/2055492159/__init__.py", line 219, in advanceClients
self.clients = list(filter(lambda c: c.advance(), self.clients))
File "/the/path/to/profile/addons21/2055492159/__init__.py", line 219, in <lambda>
self.clients = list(filter(lambda c: c.advance(), self.clients))
File "/the/path/to/profile/addons21/2055492159/__init__.py", line 126, in advance
self.writeBuff += self.handler(req)
File "/the/path/to/profile/addons21/2055492159/__init__.py", line 238, in handlerWrapper
body = makeBytes(json.dumps(self.handler(params)))
File "json/__init__.py", line 231, in dumps
File "json/encoder.py", line 199, in encode
File "json/encoder.py", line 257, in iterencode
File "json/encoder.py", line 180, in default
<class 'TypeError'>: Object of type 'map' is not JSON serializable