The liability by holding out, in case of retiring partner, continues up to:

Partnership Act section 32(3) generally continues a retired partner’s liability to third parties for acts that would have bound the firm until public notice of retirement is given. Merely informing the other partners does not supply that public notice. The proviso protects a retired partner against a third party who dealt with the firm without knowing that person was a partner; liabilities already incurred and agreed discharge require separate analysis.