No major gotchas that we've found. CheckBook 2.5.7 looks good on our test Mac with the OS X El Capitan GM installed, except for an issue related to fonts with proportional digits, an issue where "wide" years, like 1999, may not render the fourth digit in a date picker, and a situation where the Account Summary progress indicator may not appear. We've got those fixed up in version 2.5.8, which moved into beta a few days ago. When we get to a final candidate we're thinking about making it public, like we did with 2.5.7, so you can get it a couple of weeks early

.