The T engraved on the inside of the bag means it was produced in 2015.

Since 1945, Hermès has used a "1-letter stamp" to represent the year of manufacture of the product. From 1945 to 1970, 26 letters from A to R were selected in order each year.

From 1971 to 1996, a circle was engraved in addition to the 26 letters A to R. From 1997 to 2014, the 18 letters from A to R were engraved with a box. In 2015, it was the letter T, in 2016, it was the letter X, in 2017, it was the letter A, and in 2018, it was the letter C.

Since 2015, not only have the boxes outside the letters been eliminated, but the letters S, U, V, W, Y, Z, and B have also been skipped. One theory is that the letter S is easily confused with the special "S" seal, the U looks too much like a horseshoe print, and the B sounds too ugly.

Extended information:

Hermès “Birkin” bag year code table

1997-A1998-B1999-C2000-D2001-E2002-F2003-G2004-H2005 -I2006-J

Explanation of the grade mark at the opening of the Hermes "Birkin" bag

The "Λ" symbol indicates that the leather is taken from wild crocodiles and is the most expensive. Those marked with the ".." symbol mean that the leather is obtained from artificially raised crocodiles. If there is an "S" engraved under Made in France, it means it is a discount product.

Baidu Encyclopedia——hermes