Apart from the latest release of SNOMED CT, Snow Owl allows browsing and editing older versions of SNOMED CT. You can also switch between versions of ICD-10-UK, OPCS-4, Mapping Sets, Value Sets, and Local Code Systems.
To select a version, open the Code Systems View. You can see a list of the terminologies that are supported in Snow Owl. Expand the selected terminology, then expand Versions and double-click on the version you want to switch to. A dialog will pop up asking you to confirm to switch to the selected version.
Please note that the tree in the SNOMED CT View might also change, since older SNOMED CT releases used to have different hierarchies (e.g. Disease used to be a top-level concept).
A way to verify that you are working with the selected release is by opening the root concept in the Concept Editor where the information about the version is listed as a synonym. It is also indicated in the Code Systems View and on the Status Bar.
