Is there a list of system configs supported for the PHP SDK ? I am able to install the 2.6 SDK on Ubuntu 16.04.6 LTS which gets you PHP 7.033 only . When i upgrade to php 7.3 X the installation will fail.
You can find list of supported PHP versions here https://www.php.net/supported-versions.php
Could you show commands you are executing, and output with the failure?
I will try when i have time to document or use screen cast to install. The one which failed for me was taking a 16.04 LTS Ubuntu system, upgrade to PHP 7.3 and then try to install couchbase SDK