When using a system image or firmware all settings and configuration data on the ctrlX CORE are lost. Like mentioned on the ctrlX OS web UI. You can afterwards insert a configuration file (created before) including all of this data.
For the version of your ctlX AUTOMATION - PLC app, and all others available in the system, please have a look to the "Settings -> Apps" page of your ctrlX OS web UI.
The "Firmware update" page is also still available in version 2.6: ctrlX OS web UI - Settings
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