To view the formatter version of your project, open the Files dialog box, select the Formatter Templates tab and look at the selected formatter template. It shows Version in a three-number format: <major version>.<minor version>.<build number>. Formatters with different major version numbers are incompatible. However, both are supported by the same Documenter version. Incompatibility refers only to manually-added content in a document created with an old formatter. The manually-added content will not be automatically retained by the newer formatter (Regenerate Existing Document is disabled). Minor version and build number increase do not break formatter compatibility.