As announced by the Office of Information Technology on 2/4/2021:
Notes, tips, and tricks for upgrading a Drupal 8 site to Drupal 9
You've upgraded your Drupal 8 site to 8.8+ and now get the following warning in your site's Status Report.
Whether you are an experienced Drupal developer / site administrator who has come to Georgia Tech, or an existing staff member asked to venture into the world of Drupal, you may be wondering how you should get started with using Drupal for a Georgia Tech website.
This section contains tips on how to install Drupal from scratch, how to apply routine point release updates, and how to migrate between major version of Drupal. There is also a guide to moving sites from development (either on your local computer, or on a development server) to a production environment (e.g. OIT Web Hosting). For more generic but also more official guidance, the official Drupal website has a Guide to Migrating a Drupal Site.
Per Kevin Pittman's insight posted on the GTDUG Team:
With Drupal 7.61, be aware that you're now likely to see a bunch of "SimpleXMLElement" errors on the Modules Update screen. This is caused whenever a module's project status data can't be retrieved.
There are two cases that will have to be addressed:
The following table, initially provided by the College of Computing (many thanks!) attempts to summarize the details of a large number of commonly used Drupal 7 modules and any known issues with their latest full (not development) version under PHP 7. In addition, Kevin Pittman of the College of Liberal Arts has added Drupal 9 compatibility details and removal recommendations, to help site administrators decide what to do as they review the modules installed their Drupal 7 sites.
The currently supported releases of PHP are 8.0, 8.1, and 8.2. 8.0 will reach its end of life on November 26, 2023.
Per Georgia Tech's accessibility requirements, certain fields likely need additional explanatory text accompanying them:
Video Fields (e.g. YouTube)
Any publicly available video must be captioned for end-users. MediaSpace and YouTube automatic captions are not enough to meet full guidance: any automatic captions must be manually reviewed and corrected.