OpenSync is a full-featured Open Source email client supporting multiple accounts, POP3, IMAP and Push IMAP for Android.
Its a fork of Open Source Android Email Client : K9-Mail https://github.com/k9mail/k-9
Forked from K-9 Mail Version 5.300-SNAPSHOT
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Its licensed under the Apache License Version 2.0. same as k-9.
Its mine personal attempt to make a Android OpenSource Email App with different Name, Logo & Icon to relate it with email. Its still Beta from my side as its some basic changes to orginal code of K-9. Would try to find time to add more into this app. This is noway to replace orginal K-9 Mail app or compete with them.