Yes, with some restrictions. I'm currently using the stick with Jaybird X3 (after I got the drivers elsewhere). The problem with this stick is the missing software.
It depends on the operating system and the implemented Blutooth stack.
For good stereo transmission you need high speed Blutooth 'e.g. aptX' and a suitable profile A2DP.
Windows 7 does not have it and requires suitable drivers from the manufacturer. Even better is to replace the whole stack.
Speedlink does not supply any software for this and the chipset manufacturer "CSR pls" does not offer any support here (was taken over by Qualcomm in 2015).
Windows 8 and 10 have a newer and extended stack that supports A2DP native...
I also have reception problems with the Speedlink stick.
Recommend switching to the stick from Trust (CSR chipset with drivers) or Asus (Broadcom).

Yes, Bluetooth 4.1 is backwards compatible.