iPhone - Network Provider Settings Update

After being in airplane mode for an hour or so - after i turn off the airplane i receive a popup “Network Provider Settings Update” with the options - “not now” and “update”. I remember i watched in some video a long time ago that this popup is shown when there is an imsi catcher nearby, but on Apple’s website it is stated that this update is genuine.
Is it safe to update this? Or should i click on “not now” ?