Fatal error: Call to undefined method CJFunctions:

After upgrading from v3.5.6 to v3.6.0 I tried to test a previously created survey. The landing page presented correctly, but clicking on the Continue button presents the user with an error:

Fatal error: Call to undefined method CJFunctions::get_hash() in /home/rbrbnaxw/public_html/components/com_communitysurveys/models/survey.php on line 2355

Backing out the change by re-installing v3.5.6 eliminates the issue and the survey operates as designed.

I would like to stay current on releases but obviously need the survey functionality to remain intact through the upgrade process.

Thanks.