Need to retrieve all the messages from the community (more than 10000 messages)

You might be able to work around it by retrieving your messages at a smaller level and iterating through your boards etc one by one.

Alternatively you could just find the message id for the first post of the year, and then iterate through them one by one to see if they exist and store them from there. It'd be a lot of calls, but it would get everything.

Just make sure to do it from a user who doesn't have access to the moderation boards and test for the message ID before retrieving it. Your filter notices and abuse reports are in the same pool of ID's.