  A search for the decay $K^0_{\mathrm{S}}\rightarrow\mu^{+}\mu^{-}$ is
performed using proton-proton collision data, corresponding to an integrated
luminosity of $5.6\,\text{fb}^{-1}$ and collected with the LHCb experiment
during 2016, 2017 and 2018 at a center-of-mass energy of $13\,\mathrm{TeV}$.
The observed signal yield is consistent with zero, yielding an upper limit of
${\cal B}(K^0_{\mathrm{S}}\rightarrow\mu^{+}\mu^{-}) < 2.2 \times 10^{-10}$ at
90% CL. The limit reduces to ${\cal
B}(K^0_{\mathrm{S}}\rightarrow\mu^{+}\mu^{-}) < 2.1 \times 10^{-10}$ at 90% CL
once combined with the result from data taken in 2011 and 2012.
