You can still download the "trial" version of 10.10 from Pervasive's web site:
http://ww2.pervasive.com/Database/Trials/Pages/PSQLSummitv10TrialDownloads.aspx. The trial version IS the retail version if you have purchased a License Key. If you're using the Workgroup Edition (Peer to Peer) you need to install the License Key on your workstation. If you bought it from Lynn, just shoot her an email. If you're using the Client/Server edition...and downloading the client...then just install it and you're good to go.
Since you can still get 10.10, I suggest that you don't mix builds.