The Cricut Personal requires 1.45 and the Cricut Create and Cake mini require 1.65.
If CCR doesn't prompt you to update the firmware (you may have pressed Skip at some point) here's how you go about forcing the update.
(These instructions do not apply to the Cricut Mini, Expression 2 or the Imagine. Those machines are updated using Cricut Sync.)
1. Connect your Cricut to your computer
2. Open CCR and login
3. Hold down the Stop button on the Cricut and press the Power button
4. Release the power button but keep holding down the Stop button.
The Cricut will beep once. Keep holding down the Stop button until it beeps a second time. (It takes a while)
5. When it has beeped the second time release the Stop button. The Cricut will power on and some of the keys should be lit up.
6. If it has worked correctly you will see this on your CCR screen:
7. Click on the down arrow and select the Cricut model you want to update. Then you'll see this screen. (The Version info will differ depending on the Cricut you selected):
8. Press the Update button and follow the instructions there (you'll be putting it back in update mode).
9. Follow the onscreen instructions to update your firmware.