Q. What are some reason why existing/already installed custom extensions in the {app_root}/extensions directory do not have their .xml files loaded/applied (or get lost) after an upgrade?
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Q. What are some reason why existing/already installed custom extensions in the {app_root}/extensions directory do not have their .xml files loaded/applied (or get lost) after an upgrade?
From which iTop version to which iTop version are you upgrading?
Are the proper file permissions in place on the extensions in the app root/extensions folder?