A Form 4A (Certificate of Continuation), replaces what used to be the fourth certificate of renewal.
A Review of The Sequence of Forms
The first certificate of involuntary admission, or Form 3, is statutorily limited to two weeks duration; the first certificate of renewal, or Form 4, is limited to one additional month; the second certificate of renewal is limited to two additional months; and a third certificate of renewal is limited to three additional months. After the third certificate of renewal, if the patient still meets the criteria for involuntary admission, the patient would become subject to a certificate of continuation or Form 4A. A first and any subsequent certificate of continuation is also valid for a period of three months.
– A Practical Guide to Mental Health and the Law in Ontario, Chapter 3: Assessment and Hospitalization Under the Mental Health Act (pg 3-16)