Joint and several liability of partners ensures tax obligations attach to all partners and retiring partners remain liable until notified. Partners of a firm are jointly and severally liable with the firm for tax, interest and penalty under the Act. A retiring partner remains liable for liabilities attributable up to the date of retirement whether determined or not, where the firm or retiring partner gives written notice of retirement to the Chief Commissioner. If no such notice is given within one month, the retiring partner's liability continues until the notice is received by the Chief Commissioner.