Conversation so far:
What happened with Blink-182 in 2015?
Hoppus and Barker decided to continue on without DeLonge, and enlisted Alkaline Trio vocalist/guitarist Matt Skiba to fill in for three shows in March 2015.
What happened to Blink-182's Tom DeLonge?
A record deal was finalized and sessions were booked before DeLonge's manager informed the band he intended to spend more time on non-musical activities and indefinitely depart the group.

Question: what were the legal battles?
Self-contained rewrite: What were the legal battles with Blink-182?