When last at the School of Excellence in Gagetown, (summer of 2015) the IG's and Ack IG's informed my course that the plan was (or is) to keep the C3 going for as long as possible. (The LG1 is almost finished, and will be done soon.) This solution could work for the next 10 years or so. Then the plan is to procure a 120 mm mortar system to replace the C3.
This seems to be the plan, such as there is one, for the future of Reserve Artillery. However, this solution has its challenges, and I am not at all sure if this "plan" is going to stand the test of time. It makes sense as far as it is a good low-cost system that the Reserves could maintain, train, and even take into combat. The problem arises when you look at the Reg force's need to draw gunners for operations. Conversion training on a M777 is much more difficult when the Reservist being called up has only trained on mortars.
I think it is possible, given the current level of funding for new weapons systems, that the Reg Force Artillery will be given a 120 mm Mortar to replace the M777 and C3, with the Reserves getting 81 mm Mortars. Given that the cost of maintaining and training on the M777 is so high, it might be the low-cost way of keeping some indirect fire capability in the Canadian Army. I hope this does not happen, but it is the kind of thing I have come to expect. Alas, maybe I have become too much the cynic.