ALBUQUERQUE, N.M. (AP) — Frankie Valli, whose legendary falsetto defines the sound of the 1960s rock group the Four Seasons, has cancelled the remainder of the band’s 2026 tour dates, citing health concerns. “I’m so sorry to disappoint the folks who have purchased tickets to my shows, but I have decided to take the rest of the year off from touring to focus on my health,” the 92-year-old singer wrote on social media Friday. Valli, the frontman and only original member still performing with the Four Seasons, launched an extended farewell tour billed “The Last Encores” in October 2023. Shows scheduled for April of this year were rescheduled to dates in summer and fall. Now, all eight performances remaining for 2026 in cities from Scottsdale, Arizona, to Detroit have been called off entirely. The Four Seasons found fame in the 1960s, but the band’s hits –- from “Sherry” to “December 1963 (Oh What a Night)” –- span decades.…