Sadly, SDK versions earlier than 2016 R2 are no longer available and are unlikely to return in the future, I am guessing that you want it for use with Faceshift?
Somebody else today asked the same question as you. Here's a link to that question and its responses. Thanks!
I may have got lucky. Digging the net for undeleted SDK links, I came across what seems to be a working download link for the 2014 Gold SDK (also known as R1) from Intel's Chinese mirror site. I remember that this was recommended by Intel as an alternate download method of the full install package when RealSense first launched, for people who couldn't get the web installer to work with their camera. It was recommended by Intel support staffer David Lu, so you can feel confident in using it.
Here's the link. It's a very slow download of a 1.4 gb file from this Intel China server, so you may want to start it running and then go and do something else for a while!
Edit: I should add that the 2014 R1 SDK was designed for the F200. R200 support was not introduced until R2. So if you have an R200 or SR300 camera, it may not work for your camera.
Edit 2: for those who need them, the F200 driver file installer (drivers only - not the SDK) from November 2014 is still available for download on the Creative website.
R1 also contains the emotion detection feature that was removed in later versions, presumably due to Apple purchasing the company (Emotient) that provided that third-party component.
I managed to track down a link to R1's release notes.
Maybe Intel US could download it and put the file on their own server for much faster download, if they wish to be able to provide this historical version again. I have also burnt the installation file to an offline dvd as a backup measure.
I waited til the download was complete and I could run it before posting this message, just to make sure the file's integrity was sound. It seems to be fine.
I'm really glad that I could find that SDK to help you and others who wanted it for Faceshift. Good luck!
I don't know if this will be of use to you if you are primarily using the SDK for Faceshift, but I dug out my archive of offline PDF manuals for the 2014 SDK and attached them to this message as a zip file. These manuals contain a lot of script samples.
Realsense-2014-Docs.zip 10.1 MB
This message was posted on behalf of Intel Corporation
As I mentioned in https://communities.intel.com/thread/109053, thanks to MartyG's awesome reply, I was able to find version 18.104.22.168526 of the SDK on the Chinese server. You can download it from http://percsdk.qiniudn.com/intel_rs_sdk_offline_22.214.171.124526.exe and I suggest you to get it as soon as possible as this link can also come down any time.
I hope this help.