Listed below are the latest map release dates.
OS Explorer OS 1:25,000, OS 1:25,000 HD
and
OS Landranger OS 1:50,000, OS 1:50,000 HD
1st March 2019
1st December 2018
1st September 2018
1st June 2018
1 March 2018
1 December 2018
OS Vector Map Local Colour
1st January 2019 - a full update
1st October 2018 - a full update as the OS has changed some small details in how the map is drawn.
GroundRanger
1st November 2018 - a full update.
OS Open Map Local
1st October 2018 - a full update.
OS Road Map - 1:250,000 scale
1st June 2018 - a full update.
OS GB Map - 1:1,000,000 scale
1st January 2019 - a full update.