Siebel Global Deployment Guide > Deploying with Global Time Zone > About Global Time Zone and Universal Time Coordinated (UTC) >
Guidelines for UTC and Non-UTC Deployments
This topic is part of About Global Time Zone and Universal Time Coordinated (UTC).
This topic describes some guidelines that apply for deploying with UTC, or for deploying without UTC. Additional requirements are noted in other topics to which they apply.
CAUTION: Once you have already deployed your Siebel applications using UTC and created user date-time data in UTC format, it is not supported to stop using UTC by setting the Universal Time Coordinated system preference to FALSE. Otherwise, incorrect time stamp values may be created and displayed.
If you do not want to deploy with UTC or are not ready to do so, it is possible to set the Universal Time Coordinated system preference to FALSE in limited circumstances:
- For a new installation, you can set Universal Time Coordinated to FALSE after completing installation steps, as long as you have not created any user date-time data in UTC format.
- For an upgrade to version 8.0 from a prior Siebel version deployed without UTC, Universal Time Coordinated may be either FALSE or TRUE (depending on the version you upgrade from). You can set this system preference to FALSE, as long as you have not created any user date-time data in UTC format, and have not converted historical date-time data to UTC format.
For more information, see About UTC System Preferences and Setting UTC System Preferences.
CAUTION: For an upgrade to 8.0, if Universal Time Coordinated is TRUE following the upgrade and you do intend to deploy with UTC, you must run the UTC conversion utility before any new date-time data is created in UTC format. For details, see Converting Historical Data to UTC.
For an upgrade to version 8.0 that you will deploy with UTC, you perform all UTC conversion steps within the overall context of upgrade and roll-out processes described in Siebel Bookshelf documentation. For example, for deployments using Siebel Replication Manager, all regional nodes must be synchronized prior to upgrading, then re-extracted after upgrading and converting to UTC. For more information, see Going Live with Siebel Business Applications, Siebel Database Upgrade Guide, and Siebel Remote and Replication Manager Administration Guide.
If you deploy with UTC for new or upgrade deployments, you must set the Default Time Zone system preference. See About UTC System Preferences and Setting UTC System Preferences.
When deploying with UTC for new or upgrade deployments that contain custom date-time fields, you must perform the tasks in Enabling Custom Date-time Fields and Columns for UTC.
Deploying Siebel applications using UTC does not require you to set the operating system clock for the database server machine to UTC (a GMT time zone without DST). This optional task is described in Setting the Database Server to UTC.
Siebel eScript provides a set of methods for working with UTC data, along with methods for non-UTC date-time data. Use the appropriate methods for your deployment. All processing of UTC data performed by eScripts is completely independent of the UTC conversion capabilities of the Application Object Manager. For information about the UTC methods in eScript, see Siebel eScript Language Reference.
If you import appointment or activity data into the Siebel application (with UTC on) from another system that does not use UTC, additional requirements apply. For more information, see Converting Historical Data to UTC.