I’ve tested Digests version 2.2.23 and Smartfeed version 2.2.26 for compatibility with phpBB Version 3.0.12.
Smartfeed works fine, however attempts to install Digests 2.2.23 using the archive written for phpBB 3.0.11 will fail in /includes/functions_messenger.php. So I have corrected the archive and published it here. It will take some time for the update to be applied on phpbb.com.
Both archives have been updated to state that they work with phpBB 3.0.12.