If you are upgrading to version 4.5 of Iguana, you should note that the log file format used in version 4.5 is different from the log file format used in previous versions of Iguana. The new log file format allows messages that are larger than 1 MB in size.

When you upgrade, the log file for the day on which you have upgraded continues to use the old log file format (the format used in versions prior to 4.5). This ensures that you can successfully roll back from version 4.5 of Iguana to your older version on the day that you upgrade if you encounter an unexpected problem.

To ensure that all users of your Iguana server know about this issue, the following message appears whenever any Iguana user logs into the upgraded server for the first time:

This message is also added to the logs.

When the upgraded server creates new log files, they are created in the new log file format. One log file is created each day, which means that the first log file in the new format is created the day after your upgrade is installed.

	If you roll back from version 4.5 of Iguana to an earlier version on any day after the day that you upgrade, all new log files created by version 4.5 of Iguana cannot be read by your old version of Iguana.

	For a complete list of important issues that may affect you when you upgrade from version 4.1 of Iguana to version 4.5, see Important Issues When Upgrading to Version 4.5.