Using SOS 4.0 Client license for 3.5.3

[Rakhi]

We are using SOS version 3.5.3 purchased originally with 9 licenses. 2 months back (May 2004) we purchased 2 additional licenses. In the license keys that we received it was mentioned that the same are for Source Offsite Classic Edtion 4.0.
Can I use the licenses with 3.5.3.? If not, what should I do now? Shifting to 4.0 is not an option for us. We plan to continue with 3.5.3

[lbauer]

If you have SOS 4.0 licenses, they will not work in an SOS 3.5.3 server. You can email sgstore@sourcegear.com to exchange your licenses for 3.5.3 licenses.