In this paper, an updated catalog containing averaged values of [Fe/H] is presented for FGK stars on and near the main sequence. The input data for the catalog are values of [Fe/H] derived from weak and moderately strong lines and published before 2005 July 1. Those data are corrected to a uniform temperature scale, and a statistical analysis is then applied to a subset of the data that did not contribute to a previous version of the catalog. In this way, it is found that an accurate zero point for the catalog can be established with an rms error of 0.005dex. After corrections are applied to a number of the newly added data, it is shown that those corrections help to produce satisfactory zero-point coherence among the catalog entries. Standard errors that are derived for the catalog data are shown to be accurate. It is also shown that those standard errors are based on pervasive scatter in the input data, as is expected if those data are affected by genuine random effects. Samples of the metallicity catalog and an accompanying temperature catalog are displayed and discussed. To make possible an effective extension of the catalog to stars without catalog entries, a database containing photometric metallicities derived by Nordstroem et al. (2004, Cat. <V/117>) is considered. Standard errors for those metallicities are derived, and zero-point corrections required to put those data on the catalog zero point are presented.