I love many things about my new Galaxy s7 however the native mail app is NOT one of them... So I thought I would share the CyanogenMod built Email.apk and Exchange2.apk files I pulled from an older rooted phone as replacements. The CM email app is my favorite as it is simple and very fast for IMAP/POP accounts and supports auto push for IMAP unlike the AOSP version. These files are from CM 13 (Android 6 Marshmallow) and all credit for their packaging and development goes to that amazing community - beyond the AOSP provided base of course
To successfully install don't forget to first turn on "unknown sources" under Settings/Lockscreen and security. Exchange2.apk is only needed to connect to Exchange servers. All that is needed is to download and then click on from your file manager...
As a helpful side note you can disable the native email app with Package Disabler Pro
(or similar) app.