There is no single "official" one. The best known for PES 2015 is The "Classic Patch" by various modders (e.g., from PES-Patch.com or Evo-Web). Look for features like:
Step 1: Download the Patch Files Look for a pack containing: Pes 2015 Classic Patch
Installing the Classic Patch transforms PES 2015 from a "simulation of the current season" to a "simulation of football history." There is no single "official" one
The gameplay in PES 2015 is arguably better suited for these legends than modern PES games. PES 2015 was famous for its "holes"—the way the game creates space and allows for individual brilliance. This perfectly suits the playstyle of legends. In FIFA or later PES titles, the AI can sometimes feel like it plays "railroaded" football. In PES 2015 with this patch, you can dribble through a midfield with a young Ronaldinho, and the physics engine handles the flair animations beautifully. Step 1: Download the Patch Files Look for
There is a slight downside: Overpowered Stats. Sometimes, playing with a "Dream Team" of legends breaks the game difficulty. If you put 11 95-rated players against a standard AI team, the matches can become blowouts. To enjoy the patch fully, you need to play Classic vs. Classic matches to maintain competitive balance.
Once installed: