This isn’t a roadmap (Pico has been officially declared end-of-life), just a quick checkpoint for those still orbiting (like me) the Pico ecosystem.

Dependencies from the 3.0 dev branch:

"php": ">=7.2.5",
"ext-mbstring": "*",
"twig/twig": "^3.3.8",
"symfony/yaml" : "^5.4.3",
"erusev/parsedown": "1.7.4",
"erusev/parsedown-extra": "0.8.1"

I don’t have the skills to take over the project, but just for the sake of what if I try to upgrade something and see if the world is still out there, here we go. If you're experimenting, forking or sharing knowledge this could help shape your next steps, or maybe not.

• PHP 8.1 seems to work fine with the current codebase. Some cleanup might be needed, but nothing dramatic.
• Twig 3.x already requires PHP 8.1; upgrading to the latest 3.x version looks doable and mostly pain-free.
• Symfony YAML 5.4 (currently used) is still in extended support (only securety fixes) until 2029 thanks to a sponsorship. Eventually, jumping to 6.4 LTS would open more modern features and a newer horizon (active support until 2027), but it could also be a shot in the dark.
• Parsedown may be outdated (and for sure abandoned), but for now, it still gets the job done. Sometimes the old but gold mantra is exactly what you want.

Not so bad.