What does Digit Four look like on Microsoft?

On Microsoft it is the design shipped in Windows 10 Anniversary Update, shown above at full size. Older revisions are listed beneath it.

When did Microsoft add Digit Four?

Microsoft first drew Digit Four in Windows 8.0, released October 26, 2012.

Microsoft Corporation has shipped 4 versions of Digit Four. Each is dated, so you can see when the design changed.

Microsoft Windows 10

Microsoft shipped a new design for Digit Four in Windows 10, released July 29, 2015. The previous design is shown beside it.

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

What does Digit Four look like on Microsoft?: On Microsoft it is the design shipped in Windows 10 Anniversary Update, shown above at full size. Older revisions are listed beneath it.
When did Microsoft add Digit Four?: Microsoft first drew Digit Four in Windows 8.0, released October 26, 2012.
How many times has Microsoft redrawn Digit Four?: Microsoft Corporation has shipped 4 versions of Digit Four. Each is dated, so you can see when the design changed.