WordPress just released its second major update on August 11, which offers many features and user interface improvements, including the Gutenberg Block Editor, which can be used to build your website. But unfortunately, the update has made ten thousands of broken sites, An issue with how the themes handle pagination and WordPress disabling jquery migrate by default caused other websites to crash after updating to 5.5.
why WordPress version 5.5 breaks plugins
jquery-migrate is no longer be enabled by default.
after updating to WordPress 5.5 you will release that with the number of plugins(Classic Editor and Yoast etc) installed on your CMS (WordPress) will not be working. with Yoast SEO will see that the focus keyphrase wont be working
How to fix WordPress version 5.5 issues