Yes - this is true, I lost my fonts in new SW revisions as well. My old programs stopped working after FWupdate, so I had to change all my current programs to stay-in-track.
It is a pity - I am not sure it was the best decision to cut the original fonts in favor of new "hot" features. Good luck to others.

@m5stack - hey, creators of M5stack, please think twice. To cancel the commonly used and settled features of old SW releases - eg fonts - is not the best strategy of M5stack evolution I guess. The customers easily lose the trust when stealing them features that have been promised on the beginning.

In our company (producer of smart home technologies), we newer cut the original features that was promised/agreed.
I am little bit sad by this font-cut-situation as we are using Core2 modules for rapid prototyping in our labs - almost all our pre-prepared programs stopped working by FW update :-(

My workaround: In case of 2-digit Integer numbers 0-99% I used large .png pictures 0...9 eg. 200x130px and parse that integer and display it digit-by-digit.