I use MUPDF to view pdf files in an Android app. The app works fine with Samsung s6 and Nexus 5 (Android 5.x). However when using Samsung S3 (Android 4.3), it just breaks without saying anything in the debugger "the app just disappears without saying any". Is that regarding MUPDF lib? I know this lib has compiled native code. As it is a legacy code and I have to deal with it, what could be the approach to solve such issue? Thanks.
Check the Android logcat output when the app dies, that should reveal what is happening. You may need to run the app outside the debugger to get the full logcat output. If you can get this, please edit your question to add the output.
Depending on which debugger you're using, you may need to explicitly enable native debugging if you haven't already.