Upgrade existing Magento 1.9 using Open mage or get patches from it

  1. Can we upgrade our existing Magento 1.9 site using open mage ?

Yes, you can. Min PHP7, I recommend PHP7.4. PHP8 is WIP and not recommended for production.

  1. Have anyone implemented the same with their existing website ?

Yes, all our sites from M1.9 are now on OpenMage.

  1. What issues were faced during upgrading if any ?

We planned the updagrde carefully in stages as we wanted to upgrade PHP and server as well. The issues (some exceptions and errors) were resolved in the development server then we test the upgrade steps in staging server, which is a mirror of production. We didn’t face any issue in staging and production servers.

I think the number of issues you face will depend on

  1. Your current M1 version, the further away you are from v1.9.4.5, the more issues you should expect to encounter.
  2. The number of extensions and custom code you have, if you have lots of these, you may have more issues.
  3. The OpenMage version you intend to upgrade to, v20 does not guarantee BC.

Please guide us on this and what approaches we can take.

We use git in every step in our upgrade plan. It may not be the best approach for your case. It’s a bit more complicated if compare with the drop-file-in-place approach but in our case, using git offers the following:

  1. Very easy to revert the changes if anything goes wrong. We have a branch before upgrade and a branch after upgrade.
  2. We can fix issues encountered in the development server and commit them to the upgrade branch, which make it trivia to deploy the upgrade to staging and produciton.

Irregardless which approach you take, you need to take these into considerations:

  1. Do you need to upgrade the server and PHP in production?
  2. Do you need to notify the customers on shut down of the site?
  3. Which team member is responsible for which task during upgrading of production? Draw a detail sequence of actions that should take place, this will also be used as a checklist before turning on production.

Our sites were noticeably much more responsive after the upgrade, probably mainly due to new hardware and PHP7+.