I found this 20 Pesos bill when my classmate pay his Debt. Accidentally I Found out that this 20 Pesos was dated " 2008 A ".An Anonymous commented in this post that the Banko Sentral ng Pilipinas (BSP) simply ran out of serial numbers for the standard 2008 notes (702 million, if you count single letter serial numbers), so to avoid duplicate serials, the "A" was added to the 702,000,001th note onwards.

( Front View )

( Back View )

Ok this is the closer view.
* Thankyou Joshua Garay - He is the one who pay this bill to me :P