What is GPS Week Number Rollover (WNRO)?
There are millions of standalone GPS navigation devices that rely on GPS satellites to provide not only accurate position but also date and time. In 1980, when the GPS system first started to keep track of the time it could only count forward to a maximum of 1024 weeks or about 19.7 years. Once the 1024 weeks has elapsed, the counter would reset to zero (rollover) and continue the count forward. The first rollover occurred in August of 1999 and the second rollover will take place on the 6th of April 2019.

What now?
We are aware of this special occurrence and we’ve made the necessary plans to ensure that we have updates in place if needed to ensure minimal disruption to our customers. Over the past few months, we’ve performed extensive testing to determine if the WNRO will affect our range of products, both current and legacy. These tests showed that the majority of Mio GPS devices are not affected by the WNRO and will work without an update.

Will my Mio GPS device work without an update?
 The GPS signal and positioning accuracy will not be affected, but Subscriptions which have a start and an end date will be negatively affected by incorrect system date and time.

Please see the list of affected devices with Download links below :

Model GPS fix
Pilot 15 LM / Classic 400 LM / 500 LM / 700 LM Download Patch
Spirit 7700 Download Patch
Spirit 7800 Download Patch
Spirit 5100  / 5100 Base Map  Download Patch
Spirit 5400 LM Download Patch
Spirit 5450 LM Download Patch
Spirit 5670 LM Download Patch
Spirit 7000 LM / 7100 LM Download Patch
Spirit 7500 LM / 7500 Base Map  Download Patch
Spirit 7550 LM Download Patch
Spirit 7670 [ Truck ] Download Patch
Mio Combo 5207 [Truck] Download Patch