The Verified Software Toolchain is a tool for machine-checked proofs of correctness of C programs, with respect to specifications in separation logic and functional models in Coq. During the DeepSpec project (2015-2020) we have enhanced its program logic (Verifiable C) and its proof automation tools with better support for C control flow, concurrent shared-memory threads, more sophisticated separation-logic reasoning techniques, encapsulation of global variables, efficiency of separation-logic proof script execution, support for 64-bit or 32-bit C, many usability improvements, data abstraction, and strong support for modular proofs of modular programs. I will describe and illustrate some of these features.