DEAS provides Data Envelopment Analysis tools for Stata. Version 2.0 is a major update centered on a unified dea command for Stata 16 or later. It consolidates sixteen DEA model families into one interface, keeps backward compatibility with the original inputs = outputs syntax, and adds a fast Mata two-phase revised simplex engine alongside Stata's LinearProgram() IPM engine. The package supports radial technical efficiency (CCR/BCC), SBM, additive model, radial and SBM super-efficiency, multiplier form, directional distance function, cost, revenue, profit, allocative efficiency, FDH, imprecise DEA, undesirable outputs, SBM with undesirable outputs, and congestion analysis. Extension commands provide Malmquist productivity index, window analysis, network DEA, cross-efficiency, bootstrap DEA, fuzzy DEA, and research-oriented game-theoretic DEA diagnostics. The release includes Stata help files, an OECD education application, and forthcoming Stata article and supplement materials.