Trade reporting has always been out to 6 digits past the decimal but it wasnt publicly distributed and was kept to non public non tape transaction reports to FINRA. On November 17th FINRA opened a new trade reporting facility for OTC Markets specifically as the OTCBB was finally closed down. This new trade reporting facility now shows out to the 6 digit trade transactions that are reported.
This has no effect on Bid and Quotation however as that is still limited to .0001. The trades that you see at 5 to 6 digits are after arbitrage or sometimes market order transactions.