I want to roll-forward previous year's return but I used a different software last year. Can I still do that with the Taxtron software?

You can only use the roll-forward feature if you have prepared previous year's tax return using the Taxtron software. If you have not done so, you still have the option to autofill your return (if you have a CRA account). Any slips on your CRA account, any prior year amount that can be carried forward will be added to your current year tax return.