Nothing in subsection (f) of section 21-70, section 21-70a, subsection (a) of section 21-80, subdivision (1) of subsection (b) of section 21-80 and this section shall be construed to invalidate an otherwise effective notice or to validate an otherwise ineffective notice given or served pursuant to section 21-70 or 21-80 prior to June 23, 1999.