Prior to the hikes this year, you'd have to go all the way back to May 2007 for the last time the PBOC actually increased the RRR for foreign currency deposits. The latest move brings the reserve ratio to 9% as the central bank looks to try and curb excessive yuan strength.
For some context, the yuan strengthened past 6.35 against the dollar for the first time since 2018 this week. However, after the PBOC announcement here, it has weakened past the key level currently: