Is there a plugin or a way to make WP not check for updates or not show that theres a new version available.

My company uses WP as a way to communicate with some clients as private closed support sites if that makes sense. not open to the public. These sites have no reason to update to newer versions of WP and the clients are then wanting the new shiny version for virtually no reason.

Does anybody know of a way to strip WP of this ability or a plugin that doesnt show a new version is available?

thanks!