diff --git a/README.md b/README.md
index 0238847..b16e49b 100644
--- a/README.md
+++ b/README.md
@@ -24,9 +24,9 @@ repository of multicore specific packages.
 
 ```bash
 $ opam update
-$ opam switch create 4.10.0+multicore --repositories=multicore=git+https://github.com/ocamllabs/multicore-opam.git,default
+$ opam switch create 4.10.0+multicore --packages=ocaml-variants.4.10.0+multicore,ocaml-secondary-compiler --repositories=multicore=git+https://github.com/ocamllabs/multicore-opam.git,default
 $ opam switch 4.10.0+multicore
-$ opam install dune.1.9.1 domainslib
+$ opam install dune domainslib
 ```
 
 ## Development
@@ -37,9 +37,9 @@ repository:
 First install the multicore compiler and dune:
 ```bash
 $ opam update
-$ opam switch create 4.10.0+multicore --repositories=multicore=git+https://github.com/ocamllabs/multicore-opam.git,default
+$ opam switch create 4.10.0+multicore --packages=ocaml-variants.4.10.0+multicore,ocaml-secondary-compiler --repositories=multicore=git+https://github.com/ocamllabs/multicore-opam.git,default
 $ opam switch 4.10.0+multicore
-$ opam install dune.1.9.1
+$ opam install dune
 ```
 
 Then, pin a clone of this repo: