Increase WordPress minimum to 5.2.0

[Soean]

Description

In WordPress 5.2 the PHP minimum was updated to PHP 5.6.20.

Gutenberg is a feature Plugin for WordPress development. We should set WordPress 5.2 as minimum, so we can remove old PHP compatibility code and tests for old versions.

Related #15796 and #15806

[youknowriad]

We discussed this a little bit here #15565 and there seemed to be an agreement to use 5.1 as a minimum for the moment. What do everyone thinks about moving directly to 5.2. It probably doesn't hurt to wait a few more weeks.

cc @jeremyfelt @aduth @WordPress/gutenberg-core

[nerrad]

Having usage stats on what wp versions people are using would be helpful here.

With that said, I think its a reasonable assumption that most folks using the plugin understand what it is and are more likely to be on the latest WordPress (or wouldn't have to much issue with getting on the latest WordPress).

[Soean]

Thanks for your feedback.

I understand that we should not increase the minimum too early. But it should also be a goal that users update their WordPress version promptly and don't remain on the same version. If users update their plugins, they are also able to update their WordPress Core.

Yoast recently released a blog post about this topic, in the future they only support the current and the previous major WP version.

This is a feature plugin, so I think we can update the minimum supported version maybe even faster.

Gutenberg 5.9 would be June 12th. (More than a month after WordPress 5.2) or we wait for Gutenberg 6.0 after WordCamp Europe?

[aduth]

Yoast recently released a blog post about this topic, in the future they only support the current and the previous major WP version.

A takeaway I like from this is to have a policy about it, so it's known and predictable.

It's unclear what benefit there is in waiting? Or in supporting older versions at all? Conversely, there is some benefit in not waiting, as noted by referenced issues of the original comment (removing "baggage").

[youknowriad]

Yes, documenting this process would be great. It's not the first time we have a discussion about this. Let's have it once and make it a no brainer for the future.

[gziolo]

In #18414, I also see a change in the config file for PHPUnit:

gutenberg/phpcs.xml.dist

Line 6 in 1e359a8

<config name="testVersion" value="5.6-"/>

I think Travis file doesn't run PHP 5.2 and 5.3 anymore:
https://github.com/WordPress/gutenberg/blob/master/.travis.yml

[Soean]

@gziolo Thanks, I added the change to this PR.

[youknowriad]

Let's do that in the next plugin release and maybe even consider 5.3 soon.