Do you need employer after i-485 is filed?

[iaskywalker]

Category EB3
Current Status H1B

Employer1 I-140 approved
Filed I-485 and I-765 when dates got current and moved back in Oct-2007
I-765 EAD approved and have been renewing it.

July-2015 H1B transferred to Employer2

With priority dates moving close what steps should I take? Should I move I-140 to new employer? Do I need the original employer?
Please advice any information would help.