How to copy previous fixversion version value to another custum field

[siva]

Here i am using filter subscription for fix version update. Only updated fix version value is shown in the email notification. But i want both previous and current fix version values (transition from ... to ...).

So, I am thinking to copy old fix versions to new custom field. Here i am planning to use the script runner. Does anyone has written script of that(copy the previous fix version to another custom field)? Any other suggestions for this issue are most welcome!
Thanks in advance.