(b) On or before the expiration of the probationary term of a person appointed for such term on or after July first, two thousand fifteen, the district superintendent of schools shall make a written report to the board of cooperative educational services recommending for appointment on tenure persons who have been found competent, efficient and satisfactory and, in the case of a classroom teacher or building principal, who have received composite annual professional performance review ratings pursuant to section three thousand twelve-c or section three thousand twelve-d of this article, of either effective or highly effective in at least three of the four preceding years, exclusive of any breaks in service; provided that, notwithstanding any other provision of this section to the contrary, when a teacher or principal receives an effective or highly effective rating in each year of his or her probationary service except he or she receives an ineffective rating in the final year of his or her probationary period, such teacher shall not be eligible for tenure but the board of education in its discretion, may extend the teacher's probationary period for an additional year; provided, however that if such teacher or principal successfully appealed such ineffective rating, such teacher or principal shall immediately be eligible for tenure if the rating resulting from the appeal established that such individual has been effective or highly effective in at least three of the preceding four years and was not ineffective in the final year. At the expiration of the probationary period, the classroom teacher or building principal shall remain in probationary status until the end of the school year in which such teacher or principal has received such ratings of effective or highly effective for at least three of the four preceding school years, exclusive of any breaks in service, during which time a board of cooperative educational services shall consider whether to grant tenure for those classroom teachers or building principals who otherwise have been found competent, efficient and satisfactory. Provided, however, that the board of cooperative educational services may grant tenure contingent upon a classroom teacher's or building principal's receipt of a minimum rating in the final year of the probationary period, pursuant to the requirements of this section, and if such contingency is not met after all appeals have been exhausted, the grant of tenure shall be void and unenforceable and the teacher's or principal's probationary period may be extended in accordance with this subdivision. Such persons shall hold their respective positions during good behavior and competent and efficient service and shall not be removed except for any of the following causes, after a hearing, as provided by section three thousand twenty-a or section three thousand twenty-b of this article: (i) Insubordination, immoral character or conduct unbecoming a teacher; (ii) Inefficiency, incompetency, or neglect of duty; (iii) Failure to maintain certification as required by this chapter and by the regulations of the commissioner. Each person who is not to be so recommended for appointment on tenure shall be so notified in writing by the district superintendent not later than sixty days immediately preceding the expiration of his or her probationary period.