The Preferred Roaming List (PRL) is a file located in your phone, and it is used to acquire both the Sprint Network and Sprint roaming partner's network for you while you are roaming off the Sprint Network. Sprint updates the PRL a few times a year to provide you with new domestic digital roaming coverage or with international roaming coverage or to make other necessary adjustments.
Sprint sends PRL updates to phones Over-the-Air (OTA) as needed. However, you can also proactively receive PRL updates using your phone's settings. For instance, newer phones have a menu screen to perform a PRL update, Settings > Phone Info > Update PRL. The phone will check for an update and complete the transaction in less than a minute.
Mobile Broadband Cards receive PRL updates through Sprint Smartview Auto Updates.
A PRL update will not:
Improve signal strength on Sprint Network or off-network roaming areas
Help with dropped or blocked calls, or coverage holes
Help with wireless web issues
Correcting misrouted calls when roaming