A foundational influence on hard rock and heavy metal — and one of the bands that helped make San Antonio the Heavy Metal Capital of the World — Britain’s UFO has been at it more or less consistently since forming in the late ’60s. Lineup changes have been frequent over the band’s five decades, but vocalist and songwriter Phil Mogg has been a constant, helping keep its sound imminently recognizable. In a career that’s spanned 22 studio albums, there have clearly been some soft spots in the act’s body of work. Even so, it’s hard for anyone to deny UFO’s overall influence or legacy. Hard rock and metal fans should see this show as a perfect opportunity to brush up on the development of the genres and to bid farewell to the band as a touring entity. The tour is being billed as Mogg’s last.