Scenario: Upgrading the PHP version from 5.5 to 5.6 on a Centos 6.10 live server. Why on a live server? Mostly because there was no other choice. Researched many days before taking the final call just because I didn't want downtime in the server to avoid double work. So here we go.
Centos: 6.10, PHP Old: 5.5, PHP New: 5.6.40
Every(most) internet pages will ask you to follow a few steps like getting the repo ready, clearing the old repo, removing the installed modules and then installing the new one. But during the process, I have encountered with the following error, especially with a repo called Webtatic, which I believe is an obsolete repo. I have removed the repo, cleared the files, etc. But while following the steps, I still encountered the error. Here is the error
Error: Package: php55w-pecl-gearman-1.1.2-1.w6.x86_64 (@webtatic)
Requires: php(api) = 20121113-64
Removing: php55w-common-5.5.38-1.w6.x86_64 (@webtatic)
php(api) = 20121113-64
Obsoleted By: php-common-5.6.40-11.el6.remi.x86_64 (remi-php56)
php(api) = 20131106-64
Now it sounds like a fairly simple dependency error. Which is, but unfortunately there is no much info on how to get rid of the error without causing any dependency issues or future errors. There is why you need to follow step 7 mentioned below. If you are doing the upgrade from scratch, follow from step 1.