Once you have a Davinci EVM than you have access to the prior versions of the software package as well. To gain access to these you will have to register your EVM through www.ti.com/davinciregistration which will give you access to the updates site through a link on the same page. This updates site contains the current version of the EVM software as well as prior releases.
Note that this software is only available to customers who have purchased and registered a Davinci EVM.