Some stations have several coordinates supplied in the ITRF2008 solution. Each coordinate (position and velocity) is identified by an integer number called solution number (soln). Coordinates for each soln are valid for a period supplied in the discontinuity files. These periods may be different from the periods stored in the epoch block of the SINEX file which correspond to the observation spans used to determine ITRF2008 coordinates. They do not always reflect the exact epoch of the event that cause the discontinuity in the position time series when it is known that's why these files supply complementary information.