What does Postbox look like on Samsung?

On Samsung it is the design shipped in One UI 8.5, shown above at full size. Older revisions are listed beneath it.

When did Samsung add Postbox?

Samsung first drew Postbox in Touchwiz 2.0, released April 26, 2013.

Samsung Electronics has shipped 26 versions of Postbox. Each is dated, so you can see when the design changed.

Samsung Touchwiz 7.1

Samsung shipped a new design for Postbox in Touchwiz 7.1, released September 21, 2016. The previous design is shown beside it.

✳ marks a release that redrew this emoji. The rest re-shipped the design unchanged.

What does Postbox look like on Samsung?: On Samsung it is the design shipped in One UI 8.5, shown above at full size. Older revisions are listed beneath it.
When did Samsung add Postbox?: Samsung first drew Postbox in Touchwiz 2.0, released April 26, 2013.
How many times has Samsung redrawn Postbox?: Samsung Electronics has shipped 26 versions of Postbox. Each is dated, so you can see when the design changed.