I noticed that after the upgrade to 2.5.1, the app size increased considerably. I did a git bisect run which shows
commit 3c07bc3abc93228f7c6704417065895793645564 Author: Ricki Hirner <email@example.com> Date: Fri Apr 19 01:55:55 2019 +0200 Use Conscrypt; show progress bar when loading account activity
as the offending commit.
App sizes before this commit
8,6M ./app/build/outputs/apk/standard/debug/app-standard-debug.apk 5,6M ./app/build/outputs/apk/standard/release/app-standard-release-unsigned.apk
After this commit
12M ./app/build/outputs/apk/standard/debug/app-standard-debug.apk 8,7M ./app/build/outputs/apk/standard/release/app-standard-release-unsigned.apk
So, about a 50% in size increase.