Currently, it looks like 4.2.1.8, until the "upgrades" has been completed and an official 5.x.x.x is available from ST. Packet loss used to disappear with the newer version(s), but lately has returned. Sooooo, it doesn't look like there's any benefit in upgrading. But that's just my opinion.
128K|21%|13SNL|36 Menlopark 2530