Tennessee Code Title 6. Cities and Towns § 6-54-139

(a) If a municipality:

then any action or proceeding in any court to set aside the charter of such municipality or to otherwise challenge the legality of the municipality's existence as a political subdivision of this state must be commenced within ten (10) years of the date the municipality was first incorporated.

(b) This section shall apply to any municipality meeting the requirements of this section incorporated prior to or on or after June 10, 2011.

(c) With respect to any municipality which meets the requirements of this section, whether in existence ten (10) or more years on June 10, 2011, or after June 10, 2011, the adoption of the charter, the incorporation of territory as a municipality pursuant to the general laws of this state and the election of officials of such municipality are hereby ratified and validated in all respects; and no flaw or defect or failure to comply with any requirement of incorporation shall invalidate the territory's status as an incorporated municipality or invalidate any ordinance passed by the governing body of the municipality.