Full error:

Fatal error: Call to undefined method 
Jetpack_Simple_Payments::is_enabled_jetpack_simple_payments() in wp-content/plugins/jetpack/modules/widgets/simple-payments.php on line 480

Steps to reproduce the issue

This issue happens when updating from Jetpack 6.2.1 to Jetpack 6.3.2.

More info.

  • Based on the error itself, I think the update process is not complete, so it shows that error. There are more thoughts from @kraftbj in 1262756-zen
  • This error is mentioned in this PR #9456 (comment) . I am not sure if this issue can be resolved with this PR.

What we expect

We may investigate into this issue and avoid the update process causing this kind of issue.

Temporary solution

  1. Log in to your site via FTP or File Manager
  2. Delete the existing Jetpack plugin folder in wp-content/plugins/jetpack.
  3. Reinstall Jetpack plugin via WP Admin or manually https://codex.wordpress.org/Managing_Plugins#Installing_Plugins