The 19.5 version of the Claris FileMaker product line includes security related changes.
Users of all FileMaker v19 products SHOULD read the release notes for the new version.
For those planning to upgrade immediately: there are many product changes that may cause new behaviours in the product for your users. While we hope the changes are beneficial, any change is disruptive. In some cases, you have have implemented work-arounds that are no longer necessary. In other situations, the changes may affect the way that you work with FileMaker.
For those planning to defer the upgrade: Be sure that your systems are not going to be susceptible. The release of information about security fixes in the new version provides bad actors with retrospective information about previous versions. If you are not upgrading, ensure your systems are not exposed to the known security risks.