sidenote: I have nothing against the sleeptime. it isnt a bad Idea and if you are limited to a country anyway (for nexample because you target users from that country, it’s negligible.
But the problem I have with the presentation of it. The newsletter says “new feature”, which is imo quite misleading. a cpanel update which has new stuff can be called a feature, for example but this is just a limitation.
prefixing the email with important wont help here, as users may ignore the word (after all words like these are overused as hell) and think that he doesnt need the new feature and wont care because he doesnt need extra features when stuff works already nicely enough.
this in my opinion should have been called what it is right in the title, a new limitation for free users, simple, easy to userstand and most importantly, not misleading.