Use APKPure App
Get Save my Attach old version APK for Android
Faites vos achats sur Google Play sur le Web, et profitez-en instantanément sur votre téléphone ou votre tablette Android, sans synchronisation.
Save the GMail attachments to the SD-card. Tap on "Preview" button in the GMail and select "Save ..." from the list.
Works with Email app also (use "Open").
Please note: this app doesn't have a launch icon! You could open it only from your GMail app by tapping a "Preview" button