Bank account holders can continue to use their old format cheques for another three months as RBI has extended the deadline for banks to issue new cheques with uniform security features till March next year.As per the earlier direction to all banks, RBI had fixed 31st December of this year as the last date for phasing out non-CTS 2010 Standard cheques.The homogeneity in security features of the new standard cheques will act as deterrent against frauds and the fixed field placement specifications facilitate easy clearing of the cheque at drawee banks' end.