What does バスタブ look like on HTC?

On HTC it is the design shipped in Sense 8, shown above at full size. Older revisions are listed beneath it.

When did HTC add バスタブ?

HTC first drew バスタブ in Sense 7, released 2015年3月30日.

HTC Corporation has shipped 2 versions of バスタブ. Each is dated, so you can see when the design changed.

HTC

HTC Corporation has drawn バスタブ 2 times. Every revision HTC has shipped is below, newest first.

What does バスタブ look like on HTC?: On HTC it is the design shipped in Sense 8, shown above at full size. Older revisions are listed beneath it.
When did HTC add バスタブ?: HTC first drew バスタブ in Sense 7, released 2015年3月30日.
How many times has HTC redrawn バスタブ?: HTC Corporation has shipped 2 versions of バスタブ. Each is dated, so you can see when the design changed.

HTC artwork for this emoji spans 2015 to 2016.