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Fossify Messenger vs. QKSMS
(lemmy.ml)
F-Droid is an installable catalogue of FOSS (Free and Open Source Software) applications for the Android platform. The client makes it easy to browse, install, and keep track of updates on your device.
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To my knowledge QKSMS/Quik tries to do something way bigger, like multiple protocols.
I recommend DekuSMS. They have AES encryption for people both using the app, and it just works well.