After upgrading from CRM 2013 SP1 to CRM 2015 we found we could no longer use the CRMSvcUtil.
We pinned it down to when using the /generateActions parameter.
CrmSvcUtil.exe /url:https://<organizationUrlName>.api.crm.dynamics.com/XRMServices/2011/Organization.svc /out:<outputFilename>.cs /username:<username> /password:<password> /namespace:<outputNamespace> /serviceContextName:<serviceContextName> /generateActions
We would get the following error, even through we had the correct version of the CrmSvcUtil and sdk ddls.
Exiting program with exception: Could not load file or assembly 'Microsoft.Xrm.Sdk, Version=126.96.36.199, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
After logging a call with Microsoft they gave us a config file for the utility which fixed the problem. If you having this issue, download the config file and place it in the location of your CrmSvcUtil.exe utility. You should then have no problems.
You can download the config file here: https://www.dropbox.com/s/9ctb4vn1mprs9ez/CrmSvcUtil.exe.config?dl=0