From Minecraft Wiki
May 14, 2009
- Unlike other pre-classic versions, this does not use a "ddhhmm" (day-hour-minute) format, but instead a "yyyymmdd" (year-month-day) format.
- Renamed "Cave Game" to "Minecraft: Order of the Stone".
- This version was once removed due to being identical to rd-161348, but later re-added to the launcher. Instead, the launcher now have two identical versions of Pre-classic.
- While the version name implies that it was released on May 15, it was actually released at 10 pm UTC on May 14 (which is midnight on May 15, Sweden time).
- "rd-20090515.json" , May 14, 2009.
- "Minecraft: Order of the Stone" – The Word of Notch, May 14, 2009.
- Quote from PisuCat» I'm saying it's identical to rd-161348. From searching around this version was added on the launcher on the 6th of August 2013, then removed (possibly renamed to rd-161348), and it has now been recently re-added under the old name rd-20090515. Edit : It has been renamed you will find this version as rd-161348.