Sonarqube v9.3 added a built-in "text" plugin. This version deconflicts itself with that plugin. Your custom rules should survive the upgrade without any special intervention but you must continue to follow careful upgrade practices to protect against loss of custom rules.
Note that this version will not work with versions of Sonarqube prior to v9.3 because it now expects the "text" language to exist instead of this plugin defining that language.