Im pretty sure matrix.org data has been and will be sharing data with law enforcement. Even if you use encryption, they collect loads of metadata. With smaller servers it depends on local jurisdiction i guess.
The moment they start rolling out any closed or paid features and the immediate reaction of the community isnt forking the entire protocol, i will ditch matrix. Ive become very trigger happy with this stuff.
Telegram reports spike in sharing user data with law enforcement | TechCrunch (techcrunch.com)
Spike is seen after arrest of telegram CEO Pavel Durov in France in august