Over time unwanted Job DSL features are deprecated and eventually deleted. Deprecated features will be removed six month after the release in which they are first deprecated. Job DSL scripts must be fixed before this time. Deprecated features are listed on the [[Migration]] page under the release in which they are first deprecated. The console log of the seed job will contain warnings when deprecated features are used. A release will be marked as incompatible in the Jenkins Update Center if features have been removed.
If you have problems migrating, ask for help on the mailing list.