I am looking for a secure chat program that:
- Works on Android 2.3+
- Is available in F-droid or as APK (Available on Google Play is not enough)
- Is compatible between versions
- Is under a free (as freedom) license
- Is as easy to setup as RedPhone (but it is even better if it does not require a phone number, as it will only be used over wifi)
Why not TextSecure? I hear you ask. Because the only APK for Android 2.3 I have found (http://www.appsapk.com/textsecure-private-sms-mms/) is incompatible with newer versions of TextSecure.
If you point to an APK and not an app on F-droid, please also link to the license, so it is clear that is is under a free (as freedom) license.