i2b2 versioning will require that version numbers for different components match, that is, versioning will not be forward or backward compatible. If version numbers from different components are not equal, the user will be required to upgrade their software.

1. The i2b2workbench.properties file contains a message version number. The version number is a hive variable for the message version contained in the i2b2 <message_header>.

1. When a user logs on, the PM client sends a null <get_message_version> tag.

<message_header></message_header><!--Optional-->
<message_body>
<get_message_version></get_message_version>
</message_body>

1. The response message from the PM cell contains the message versionin the message body tag <i2b2_mesage_version>.

<message_header></message_header><!--Optional-->
<message_body>
<get_message_version></get_message_version>
</message_body>

1. The workbench client compares the PM message version number with the version number from the workbench properties file. The two version numbers must be equal. If they are not equal, the user cannot continue until upgrading. If the version numbers are equal, the application will continue normally.