There are still more restrictions however on spending on other candidates and they would have to act like any other PAC, only helping via donating/running ads in support of (but importantly not directly by) any other candidate.

The money Biden has raised directly however can only go to the people that were on his ticket at the time the donation was made

It is current just in TestFlight (so iOS only) and the link is https://testflight.apple.com/join/BF7pq1hn

A bit biased since I am the creator, but using Lemmios has been pretty sweet!