We show ocaml-mpst, a library for safe concurrent programming in OCaml based on Multiparty Session Types (MPST). The key feature is global combinators, a typed, embedded DSL for specifying the protocol of a system of interacting processes. Such protocols are checked statically; thus, unsafe concurrent behaviour can be detected as a type error by the OCaml compiler. Until now, most MPST implementations use external domain-specific protocol description languages and tools (e.g. the Scribble toolchain), as MPST protocols are considered far from the types of a mainstream programming language. We utilise parametric polymorphism in ML and row polymorphism in OCaml in particular, achieving the one-stop platform for concurrent programming in a general-purpose language with industrial strength. The library ocaml-mpst is first presented at ECOOP 2020. This manuscript also introduces a use-case of protocol reuse utilising row polymorphism and shows recent development of ocaml-mpst, discussing the effectiveness of the approach and future work.