My project was targeting SDK27 and was working fine and heavily tested. Since google play want to target SDK28, I changed target to SDK28.
After this I started having issue connecting to server in (only) android 9. This turned out to be clearTextTraffic disabled issue as the server doesn't have https (mine is a small app). After adding android:usesCleartextTraffic="true"
in AndroidManifest.xml, this issue was solved and app is again connecting to server as before.
I also have an image upload page using MultipartUploadRequest and this was also failing after SDK28 and this is still not fixed in android 9 (it was definitely working before and is working fine even now in other android versions). So, I am almost sure this is clearTextTraffic and file upload related issue (or at least related with targetSDK change). But not sure what or how to solve this. I am using okhttp. Any help is greatly appreciated.