When you apply version 5.5.2651.32 or later of the Store.exe file on an Exchange Server computer, and then start the information store, the information store databases are automatically upgraded to a new format, and the following events appear in the event log:
Event ID: 1185
Source: MSExchangeIS Private
Type: Information
Category: General
Description: Successfully upgraded database to version version.
Event ID: 1185
Source: MSExchangeIS Public
Type: Information
Category: General
Description: Successfully upgraded database to version version.
where
version is 2.45 if you applied a Store.exe file earlier than version 5.5.2652.68, or 2.46 if you applied version 5.5.2652.68 or later.
After the databases have been upgraded to version 2.45, you can restore an earlier version of the Store.exe file on the server, but only if it is version 5.5.2651.32 or later. Similarly, after the databases have been upgraded to version 2.46, you can restore an earlier version of the Store.exe file on the server, but only if it is version 5.5.2652.68 or later. If you restore a Store.exe file earlier than the above versions, and then attempt to start the information store, you experience the behavior described in the "Symptoms" section, but the information store databases are not damaged.