- don't require pear's MDB2, Mail_mimeDecode, nor DB,
- don't require php-mcrypt,
- require php modules: pdo, openssl, session, json, pcre,
- require pear's Crypt_GPG >= 1.4.0 (for Enigma plugin).
Also, we're using Net_Sieve package from https://github.com/roundcube/Net_Sieve.git which supports PHP7.
- now uses endroid/qrcode, we have a package already and roundcubemail should depend on it