Ah, that new phone smell. We all crave it every now and then. To answer the question, it really depends on which phone you want.
You can keep your plan when you upgrade to Tab Small. The exception is when you upgrade to Tab Medium or Tab Large.
Existing Koodo customers upgrading to a phone on Tab Medium will need to take an eligible plan with Tab Medium. If you’re already on an eligible plan with Tab Medium, then you won't be required to change your plan.
If you want to keep your monthly plan when you upgrade, you have the option to pay more upfront for your phone. The more you pay upfront, the smaller your monthly Tab charge. If you have a positive Tab balance, you can use that towards the purchase of your phone.
If you want to get a phone with Tab Large, you must either already be on an eligible plan with Tab Large, or choose a new eligible plan with Tab Large.