What are the android versions on BDL?
xxBDL3050Q Android 5.0.1
xxBDL3052T Android 5.0.1
xxBDL4050D Android 4.4.4
65BDL3051T Android 4.4.4
xxBDL4051T Android 4.4.4
xxBDL4150D Android 7.1
xxBDL3550Q Android 8.0.0
xxBDL4550D Android 8.0.0
Can I upgrade the Android version on the screens above by updating the SW version?
No.. BDL SW update doesn't update the Android version running on the screen's android on board.. it only update SW running on top of the android.