What is the test for retroactively applying a new interpretation of criminal procedural rules?

By contrast to legislation, judicial decisions have been governed by a "fundamental rule of retrospective operation" for "near a thousand years." Harper v. Va. Dep't of Tax'n, 509 U.S. 86, 94 (1993) (cleaned up). Courts must apply judicial decisions announcing new interpretations of criminal procedural rules "retroactively to all cases, state or federal, pending on direct review or not yet final." Griffith v. Kentucky, 479 U.S. 314, 328 (1987). Federal courts must also retroactively apply new rules announced in civil cases, except in narrow circumstances. Harper, 509 U.S. at 97-98.