Thanks to H I Sutton :-)
Chinese JN shipyard has launched a submarine of a previously unreported class. There are currently very few details but the design is relatively small, in the order of 5-6m in diameter and ~50m long. The most distinctive feature is the extremely small sail.
In many respects the design resembles the MS200 midget submarine design from CSIC but is larger and has an even smaller sail. There is speculation on the Chinese internet that it is the HS2600 design from JN Shipyard. This is unconfirmed.
The design appears to be single-hull which is uncommon in Chinese submarine building. The upper rudder is much larger than the lower one.