My team's weekly newsletter has experienced a sharp drop in opens in March, and thanks to Litmus we were able to identify Gmail as the source. We went from approx. 2,500 Gmail opens in early March to only 200 Gmail opens last week, so it's a pretty serious loss. Is anyone aware of any recent changes to the way that Gmail handles HTML emails?

We also updated our template at the end of February, so is it possible something we changed is triggering Gmail to deliver it differently than before? Our delivery rate is good (99%+) and our emails have passed all of the Litmus spam tests with flying colors.