According to a couple of tweets from XDA TV producer and moderator Shen Ye, the upcoming HTC M8 may have the same four color versions at launch - black, red, blue and grey (or, if you prefer their hex codes: #bebebe, #33b5e5, #cc0000 and #414141). XDA is a respectable and trustable community, so this could really happen.
Unfortunately, there is still no word on exactly when the M8 will be released. HTC could officially announce it in February or March, but we don’t know if it will call it HTC One+, or HTC One 2 (the latter name sounds rather silly anyway).
Other expected features include Android 4.4 KitKat with Sense 6 UI (which will hopefully bring many enhancements), an UltraPixel rear camera, and a quad-core Qualcomm processor. HTC will probably keep the aluminum body, as well as the BoomSound front speakers for the new flagship.
Update: it appears that the four alleged colors of the M8 may not be similar to those of the original HTC One after all.