FOSS mobile OS FuriOS has been updated to version 13.06. It includes battery management improvements, modem improvements, kernel upgrades, and more. I was able to upgrade my FLX1 from 13.0 to 13.06 simply with a couple rounds of "sudo apt update" and then "sudo apt upgrade". I had no issues with my upgrade.
The main website for FuriLabs is here:
A full changelog for the update can be found ehre:
https://furilabs.com/changelog/
The store page for the FLX1 is here:
https://furilabs.com/shop/flx1/
The company has a Github page where their code can be found:
The company has a presence on Mastodon here:
https://fosstodon.org/@ furilabs