Replaces everything after the enacting clause. Amends the Illinois Pension Code. In the State Employee Article of the Code, provides that, with regard to persons subject to the Tier 2 provisions, an investigator for the Department of the Lottery is entitled to an annuity calculated under the alternative retirement annuity provisions, in lieu of the regular or minimum retirement annuity, only if the person has withdrawn from service with not less than 20 years of eligible creditable service and has attained age 55, regardless of whether the attainment of age 55 occurs while the person is still in service. Authorizes an investigator for the Department of the Lottery to establish eligible creditable service under the alternative retirement annuity provisions. Provides that a specified educational requirement for persons employed by the Department of Juvenile Justice shall no longer determine the eligibility to earn eligible creditable service under the alternative retirement annuity provisions, and authorizes the conversion of service credit to eligible creditable service. Excludes a benefit increase resulting from the amendatory Act from the definition of "new benefit increase". Establishes a deferred retirement option plan for certain police officers, firefighters, sheriff's law enforcement employees, and deputy sheriffs in the Cook County Police Department who are otherwise eligible to retire under which a participant may continue in active service for up to 5 years while having his or her retirement pension paid into a special account. Provides that the election to participate in the deferred retirement option plan must be made before January 1, 2029. Provides that the Retirement Systems Reciprocal Act (Article 20 of the Code) is adopted and made a part of the Downstate Police, Downstate Firefighter, Chicago Police, and Chicago Firefighter Articles. In the Chicago Teacher Article of the Code, provides that when computing days of validated service, contributors shall receive the greater of: (1) one day of service credit for each day for which they are paid salary representing a partial or a full day of employment rendered to an employer or the Board of Trustees of the Fund; or (2) 10 days of service credit for each 10-day period of employment in which the contributor worked 50% or more of the regularly scheduled hours (instead of one day of service credit for each day for which they are paid salary representing a partial or a full day of employment rendered to an employer or the Board). Amends the State Mandates Act to require implementation without reimbursement.