Upgrading to v18

If you are migrating from WordPress to Altis, check out the migrating guide first.

To upgrade to Altis v18, edit your composer.json and change the version constraint for altis/altis and any local environment modules to ^18.0.0.

	"require": {
		"altis/altis": "^18.0.0"
	"require-dev": {
		"altis/local-server": "^18.0.0"
	"config": {
		"platform": {
			"php": "8.1"

Once you have made these changes, run composer update and then run the wp altis migrate command:

# For cloud environments
wp altis migrate

# For local server
composer server cli -- altis migrate

Breaking Changes

Changes to the Altis platform


PHP 8.1 and 8.2 are our recommended versions of PHP for Altis. Note that there are a small number of exceptions to Compatibility in the core WordPress CMS module. See the WordPress documentation on compatibility for more information.

Refer to our PHP Version Guide for up-to-date compatibility, testing and upgrading information.

Headline Features

WordPress 6.4.2

WordPress 6.4.2 brings a host of new features, bug fixes, and improvements as well as a new default theme. There are hundreds of enhancements, new features, bug fixes, and more. The block editor alone has more than 1400 updates. These include:

  • improvements in performance,
  • updates to accessibility, and
  • modernising code and coding standards.

See the WordPress 6.4 Field Guide for more information.

Of interest to developers are new or improved features such as:

WordPress 6.4 Backward Compatibility

  • There are some changes to script loading. This change may have backwards-compatibility implications for the obsolete use of the clean_url filter
  • Attachment pages are no longer enabled by default for new installs.
  • Replacing hard-coded style tags with wp_add_inline_style() may require some developer action

Altis Dashboard

  • We reworked the login screen to be more informative and a little prettier
  • SES error messages are now displayed better in the dashboard
  • Status information in the dashboard has been improved including the addition of an environment page

Altis Core improvements

We have incorporated many updates to modules and libraries in Altis to bring in important bug fixes and improvements.