Default obfs4 bridges are all offline
All obfs4 bridges in the following two files are offline as of June 12 2019:
orbotservice/src/main/res/raw-fa/bridges.txt
orbotservice/src/main/res/raw/bridges.txt
I hear that in the long run, Orbot will use tor-android-service, which includes our up-to-date default bridges, but in the short run we should make sure that these bridges are kept in sync with our default bridges.