Avoid Modifying Out of the Box Elements

Out of the Box configuration elements should never be modified, as this will have a direct impact on Upgradeability. Any modified element will result in a Skipped Record during an upgrade, with the associated cost of reviewing and comparing the changes, and deciding which action to take.

Furthermore, modifying Out of the Box configuration elements means that any enhancements included by ServiceNow in future version will not be applied to your instance, thus diminishing the return on your investment in ServiceNow.

The following general recommendations can be followed to ensure that the upgradeability of your instance is not compromised:

1. If an Out of the Box element is not suitable for your needs, make a copy of the element and change it according to your needs. De-activate the Out of the Box version, which will still allow it to be updated without raising a skipped record. This will also allow you to more easily compare new versions of the element with your customisations.
2. Extend the functionality of your instance through Scoped Applications. This will not interfere with the Out of the Box functionality in your instance.
3. Some Out of the Box elements already support changes to their default functionality by using platform functionality. For instance, use Dictionary Overrides and Field Labels to change the default attributes of Dictionary Entries.
4. If you need to write custom code, make sure that it is localised and well documented.
5. Avoid code duplication, especially around Catalog Client Scripts. This can very easily get out of hand and make reverting to out of box especially challenging.