The reason for this decision is that use of antecedent versions may involve significant risk, which is likely to increase over time presenting safety issues. We have serious concerns about usage of 10 year old versions of our product, and we strongly encourage users of antecedent versions to put appropriate migration plans in place to move to SNOMED CT. We do understand that this takes time, which is why the expiration of the license was set a number of years in the future. The initial decision was made in 2009, a public announcement went out at that time, and information has been available on the IHTSDO/SNOMED International website since then.