Apart from the years involved, which is the extension, the expansion is the ceiling in the base year. The amount of employer EI premiums required has gone from $10,000 to $15,000. Employers who have employer EI premiums in the base year, which is 2012, of $15,000 or less can qualify for a credit. That's the expansion. It has gone from $10,000 to $15,000.
On November 18th, 2013. See this statement in context.