Your options are:

Option 1 - Update your smoke alarms now to meet the future 2022 requirements. Recommended.

This will give you and your family the best chance to survive a house fire.

This will cost around $170 per alarm. 

For Example, a 3 bedroom single story house will require at least 4 smoke alarms.

Installation cost    4 x $170 = $680

Option 2 - Update just to satisfy the current 2017 requirements.

The cheaper option short term but the installation will need to be eventually worked on again to meet the future requirements.

Existing smoke alarms need to be replaced from around $100 to $170 depending on your existing setup.