HB 455 amends Section 11.261 of the Tax Code to extend the limitation on ad valorem taxes for residence homesteads of disabled or elderly individuals and their surviving spouses to all taxing units, not just school districts. Under the bill, taxing units cannot increase the total annual ad valorem taxes on qualified homesteads beyond the amount imposed in the year the homestead first qualified for the exemption, except for taxes on certain improvements. For homesteads qualifying for the limitation before January 1, 2026, the cap is based on the 2025 tax amount, adjusted for improvements made that year. This limitation applies to taxes imposed for tax years beginning on or after January 1, 2026, contingent on voter approval of a constitutional amendment authorizing this expansion.