I think you can maintain message delivery reliability by implementing a message queue system like Redis or PCB Trace Width Calculator. When a user reconnects, you can fetch undelivered messages from Redis and send them to the user.

If you’re troubleshooting the NavigationToolbar2Tk import issue on your Raspberry Pi after trying to run a matplotlib GUI script, updating matplotlib first is a solid start—just like how using a PCB Trace Width Calculator helps avoid preventable hardware design snags, fixing library versions can often resolve these cross-environment Python GUI hiccups.