Wrong forum Does new lower CAT threshold apply retrospectively?

If someone is currently just barely under the current CAT category A Threshold based upon inheritances over the last few years and therefore has paid NO CAT in respect of the inheritances, does a 20% reduction in the CAT threshold now mean that they have exceeded their CAT threshold and owe tax?

Revenue will issue briefing notes on this and other matters soon but I would expect that the thresholds at the relevant historic gift/inheritance dates would stand on the basis of legislation in force at that time.