To update the free version download this update file into the directory or folder (normally "Appchkr") into which you originally installed the program. (Its base directory.) In the same way as for install, run the file update_chkr.cmd (Windows) or update_chkr (Linux) in that directory.
Subscribers receive the download automatically and will be prompted to allow the update. They may also download and run the update manually, as above, without waiting for the automatic download.
Update files work with the immediately prior release and insofar as possible with earlier ones but users are strongly advised to always update to the current release when it becomes available, for best results. Releases in the distant past may become incompatible with the current release update process. If so that old release may be uninstalled and the current one installed in the same folder without loss of any data. Credentials will need to be reenciphered in such a case and subscriptions reactivated. The update process preserves enciphering and activation, avoiding this nuisance.