The ENVIRONMENTAL_DAMAGE sub-event of COMBAT_EVENT_LOG_UNFILTERED has been changed from reporting an unlocalized hazard type token to a localized value. While this probably won't affect very many addons (luckily it doesn't affect MSBT since it just reports the localized value anyways), it does make it difficult to detect a specific type of environmental damage.
As detailed on wowpedia
here it previously returned tokens such as "FALLING" and "DROWNING" making it easy to detect specific types of environmental damage in a language independent manner.