"Incompatible Archive" error in WordPress 6.4.3

Jan 31, 2024: We are aware of a bug in WordPress 6.4.3 that is preventing zip files from uploading into WordPress. Your 17th Avenue theme is a zip file, so you may encounter an "Incompatible Archive" error message when installing your theme on WordPress 6.4.3. WordPress is aware of this issue (see this link) and is actively working on a fix.

While we await a bug fix from WordPress, here's what to do if you encounter this error:

  1. Go to Plugins > Add New. Install and activate WP Downgrade.
  2. Once activated, go to Settings > WP Downgrade.
  3. In the WordPress Target Version box, type 6.4.2. Click Save Changes.
  4. Next, go to Dashboard > Updates and click "Re-Install Version 6.4.2." This will downgrade you to WordPress 6.4.2.

After downgrading, you can proceed with uploading your 17th Avenue theme as normal on your Themes page.

Once your theme is installed, deactivate and delete the WP Downgrade plugin. You can then either upgrade to WordPress 6.4.3 again (this version works well other than this issue), or wait for the WordPress 6.4.4 release.