There have been no "Part 25" (they refer to the seasons as parts) DVDs as of yet. As of right now, Season 24 lasts from Episode 740 to Episode 768. We will have to wait to see is there is an 8th and maybe even a 9th DVD (there are currently 7 DVDs that comprise the Season/Part 24 Episodes) until we can draw the line between Season 24 and Season 25.
http://www.detectiveconanworld.com/wiki/Japanese_DVDs