With respect to venue in criminal matters for the towns provided for in sections 51-139, 52-25e and 54-77a, the provisions of such sections shall apply only to offenses committed on or after April 22, 1975, and the provisions of § 51-139 of the general statutes, revision of 1958, revised to 1975, shall apply to offenses committed prior to said date; but no criminal cause shall fail for having been brought to a session of improper venue.