Unlocked Videotron or Wind SGS4 - model m919v on LTE networks
I acquired an m919v version (used by Videotron or Wind in Canada). If you unlock it and try to use on an LTE capable network like Rogers or Telus, it won't run on LTE. Videotron blocks or prevents the enabling of LTE through the settings.
I downloaded and installed this magic little app, not available on the Google Play Store, but through another discussion forum. This is an older version of Phone Info app that enables you select and activate your preferred network connection whether LTE, GSM, CDMA, etc....
Essentially this over-rides the device's 'limited settings' and permits you to choose LTE. Choose 'Device Information' to enable or disable LTE as you wish.
"This device is from another 'Galaxy'!