This issue affects only GLONASS-enabled receivers. GLONASS tracking will be temporarily interrupted on receivers operating during the introduction of the leap second on December 31st, 2016. GPS tracking will not be impacted, and receivers will continue to compute a position using the GPS constellation. OEM6 receivers may report a solution integrity warning during this period. GLONASS tracking will return to normal once a new GPS almanac is automatically downloaded from the satellites by the receiver. Receivers powered-up after the introduction of the leap second that do not have a current almanac will also temporarily have difficulty tracking GLONASS satellites. An almanac will not be available on start-up if the receiver has not been used in 90 days or if the  almanac has been cleared manually by the user. GPS tracking will not be impacted, and receivers will continue to compute a position using the GPS  constellation. OEM6 receivers may report a solution integrity warning during this period. GLONASS tracking will return to normal once a new GPS almanac is  automatically downloaded from the satellites by the receiver.