The article doesn’t make this clear, strangely, but it looks like adopting this new standard will make the death count go from roughly 100,000 to 85,000.
Here’s the proper quote:
“As of 5 p.m. Wednesday, Massachusetts health officials had recorded 23,708 confirmed and probable COVID-19 deaths since the outbreak first began, so that figure is likely to drop to around 20,000 on Monday.”