HTC kicked off the roll out of Android 4.1 Jelly Bean update for the One S more than a month ago, but some carrier-bounded models have yet to receive the upgrade.
Fido customers are among those HTC One S owners who were left out from the initial deployment of the upgrade, until today.
The upgrade is pushed OTA (over the air) in waves, so not all HTC One S users might receive it at the same time. Those who have yet to be notified on the update can manually check for it by going to Settings / About phone / Software update.
Keep in mind that aside from bringing the phone's software to Android 4.1.1 Jelly Bean, the update will also upgrade HTC Sense user interface to version 4+.