Accessibility is the driving force behind this change. By April 26, 20281, public libraries with populations under 50,000 must comply with WCAG (Web Content Accessibility Guidelines) 2.1, Level AA. This Americans with Disabilities Act requirement is administered by the Civil Rights Division of the Department of Justice. And beyond that, making libraries accessible to all is an important part of the overall library mission.
While we've used accessibility plugins to add some accessible functionality to the websites, WordPress is not currently compliant to the level our sites must reach. And even if WordPress does reach accessibility, an update of WordPress, a theme, a plugin could break that accessibility.
Library Market is WCAG 2.2, Level AA compliant. Whenever they go through a major upgrade, an outside auditor checks the upgrade for accessibility.
1Update: During the transition process the deadline was pushed back from April 2027 to April 2028. However, we are still pursuing the same timeline.