  We present a detailed analysis of the possible future Sun's rotational
evolution scenario based on the 8 Gyr-old solar twin HIP 102152. Using HARPS
high-cadence observations (and TESS light curves), we analyzed the modulation
of a variety of activity proxies (Ca II, HI Balmer, and Na I lines), finding a
strong rotational signal of 35.7 $\pm$ 1.4 days ($\log B_{\rm factor}\sim70$,
in the case of Ca II K line). This value matches with the theoretical
expectations regarding the smooth rotational evolution of the Sun towards the
end of the main-sequence, validating the use of gyrochronology after solar age.
