https://www.logos.com/product/215259/center-for-new-testament-textual-studies-new-testament-critical-apparatus
Ships in antipation of the Ides of March. Can't see what the prepub savings is, if any (digital list price??).
If you're not familiar with an 'apparatus', they document non-trivial differences in the manuscripts. And since there are so many varients, they choose what to include. The one associated with Nestle (NA) typically looks at key word differences, and the more important mss's, while UBS concentrates on translational clues, and a broader grouping.
CNTTS is much more extensive ,.. which can be good, if you're interested in the more minor varients and mss's. But less good, if you're not ... the Logos display can be a challenge.
However, due to Logos' famous search capabilities, you can use it to highlight mss dating, and mss significance for easy glances.
Below, is in the new preface; note 'new coding!'. Hmmm. 'Near-term horizon' too.
"This current 2021 release is a major upgrade in that new MSS have been included, corrections have been made to numerous readings and variant divisions, and new coding has been added both to enhance the information for the user and to enable some advanced uses of the database, with some of those uses being present in the update and others on the near-term horizon for implementation."