Updated W1−W2 vs. z_AB−W1 and J−W2 vs. z_AB−W1 colour–colour diagrams with more metal-poor T, Y dwarf candidates compared to the one of Zhang et al. (2023). All the metal-poor T dwarf candidates are labelled with blue crosses and arrows and the Accident is labelled with the black cross and arrow. We over-plotted solar-metallicity M, L, and T sequences from Pan-STARRS (yellow stars, orange squares and red dots, respectively), L subdwarfs (olive squares), four Y0 dwarf, a Y2 dwarf, the Y4 dwarf (purple triangles), and a T9+Y0 system (red dot mixed with purple triangle). All Y dwarfs were identified with CatWISE photometry. Error bars are included for all sources, except for M and L dwarfs. We also show three iso-metallicity curves from the low-metallicity theoretical model LOWZ (Meisner et al. 2021) with parameters: log g = 5.0, log₁₀K_zz = 2, solar C/O ratio 0.55 in both diagrams. From left to right, the effective temperature of the model decreases from 1600 K to 500 K, with a step of 100 K and 50 K above and under 1000 K, respectively.