China Foreign Exchange Trade System (CFETS) today shortened the reference period 20 Feb

According to sources of Reuters CFETS have shortened the ref period of yuan trading against its trade-weighted basket to 15 hours from 4.30 pm local time on Friday to 07.30 am today

The sources say the latest adjustment was meant to better reflect changes in the forex market, and help curb intraday speculative trading activities. Today's mid point rate from the PBOC prior to the open was 6.8743 vs 6.8456 for the previous fix.

So China saying they want the yuan to be more market driven and transparent but on their own terms it would appear.

From the start of this year the Yuan's TWI basket has been increased from 13 to 24 currencies.