The CERN Axion Solar Telescope (CAST) searches for $a\ensuremath{\rightarrow}\ensuremath{\gamma}$ conversion in the 9 T magnetic field of a refurbished LHC test magnet that can be directed toward the Sun. Two parallel magnet bores can be filled with helium of adjustable pressure to match the x-ray refractive mass ${m}_{\ensuremath{\gamma}}$ to the axion search mass ${m}_{a}$. After the vacuum phase (2003--2004), which is optimal for ${m}_{a}\ensuremath{\lesssim}0.02\text{ }\text{ }\mathrm{eV}$, we used $^{4}\mathrm{He}$ in 2005--2007 to cover the mass range of 0.02--0.39 eV and $^{3}\mathrm{He}$ in 2009--2011 to scan from 0.39 to 1.17 eV. After improving the detectors and shielding, we returned to $^{4}\mathrm{He}$ in 2012 to investigate a narrow ${m}_{a}$ range around 0.2 eV (``candidate setting'' of our earlier search) and 0.39--0.42 eV, the upper axion mass range reachable with $^{4}\mathrm{He}$, to ``cross the axion line'' for the KSVZ model. We have improved the limit on the axion-photon coupling to ${g}_{a\ensuremath{\gamma}}<1.47\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}\text{ }\text{ }{\mathrm{GeV}}^{\ensuremath{-}1}$ (95% C.L.), depending on the pressure settings. Since 2013, we have returned to the vacuum and aim for a significant increase in sensitivity.