Recently, Riot games tried to change Sona in League of Legends to make her more interesting with a reworked passive. With above 50% winrate in SoloQ the changes were sucessful for sure. While she's not one of the most popular characters in the curent meta she is already in Riot's nerf zone as they don't want her to dominate during Worlds.
For that reason Riot Games confirmed the series of adjustments that Sona will receive and explained "Sona bumped just over the bounds for nerfs in skilled and is very close to the line for average and elite. Pairing a smaller nerf with a revert and a bugfix nerf. ".
The change's not that massive, as it only changes some stats, correct a bug and adjust her Q spell.
Sona Nerfs
These changes are planned to arrive with Patch 11.19 of League of Legends as the adjustments to all the champions are already on the PBE server.