SRM 5 to SRM 7 upgrades, earlier version of the SRM upgrades
Most of organisation might be using the SRM 5 or the earlier versions and would be looking for the upgrade or the fresh implementation.
SAP SRM has the specific upgrade path and supports as one step upgrade from SRM 4. Some customers would like to change the technical scenario to leverage the functionality; some may want to implement the new scenarios. Based on the requirements and the evaluation the decision to upgrade or implement could be derived.
The existing customers with SRM version lower than SRM 4 would benefit from the fresh implementation rather than the two step upgrade. Though the considerable efforts required the migration of the documents could be considered.
The new customers should install SAP SRM 7.02 (or the latest release).