PECL Memcache version 3.0.9-dev is unsupported

PECL memcached and memcache are not the same. (With "d" at the end)

Memcached -> https://pecl.php.net/package/memcached

Memcache -> https://pecl.php.net/package/memcache

Thanks, sure, as the project description says: "An API for using Memcached and the PECL Memcache or Memcached libraries with Drupal." Who is supposed to understand which one is used for which purpose by the Drupal module?

Anyway, on my old production server I got php-memcached 2.2.0-2 and php-memcache 3.0.8-5; on my new server I got php-memcached 3.1.3+2.2.0-1 and php-memcache 3.0.9~20170802.e702b5f-2, so I can not meet the requirements without breaking package management dependencies. Lovely for a D7 module.

More of these non-sensical opinions from memcache module.

Reported at ./admin/reports/status:

There is a problem with your memcache configuration. Please review sites/all/modules/memcache/README.txt for help resolving the following issue:
PECL Memcache version 3.0.8 is unsupported. Please update to 3.0.6 or newer.

Information like this isn't too helpful. At least I do not understand what the poet tries to tell us here.