If you are planning on upgrading to ProjectWise 10.00.02.xx, please be aware that this requires a dms convert to any pre existing ProjectWise datasource. This means that it is not possible to use a PW Admin Update 2 to connect to a pre Update 2 datasource. If you do attempt to connect, PW Admin will prompt you to upgrade tables on any pre update 2 datasource. This is not recommended unless you plan on upgrading that datasource to Update 2.
As always, it is not supported to have mixed versions of ProjectWise on the same machine. This means that installing PW Explorer Update 2 with PW Admin Update 1 (or earlier) on the same machine is not supported. You can however use PW Explorer Update 2 to login into pre Update 2 datasources. It is only logging in with PW Admin update 2 that causes the dms convert issues.