Its 'possible' but its not straight forward.
The first question is how many Topobase servers do you have? Your client must be on the same version as the server. If your server is 2009, then you will get error messages from a 2010 client. If your server is 2010 service release 1, you will need to upgrade the 2010 client to service release 1. Neither clients or servers are 'backwardly compatible'.
If you have both 2009 and 2010 topobase servers then there may be a reason to have both clients installed. The clients must be 'isolated' from each other. I've found the easiest way to do this is through a VM. Create two VMs and install 2009 on one and 2010 on the other.
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