diff --git a/alire.toml b/alire.toml
index ea1e48bd1..1e2fbed1c 100644
--- a/alire.toml
+++ b/alire.toml
@@ -27,7 +27,7 @@ minirest = "~0.3"
 optional = "~0.1"
 semantic_versioning = "^3.0"
 simple_logging = "^2.0"
-si_units = "~0.2"
+si_units = "~0.2.2"
 stopwatch = "~0.1"
 toml_slicer = "~0.1"
 uri_ada = "^2.0"
@@ -56,4 +56,5 @@ gnatcoll = { url = "https://github.com/alire-project/gnatcoll-core.git", commit
 minirest = { url = "https://github.com/mosteo/minirest.git", commit = "9a9c660f9c6f27f5ef75417e7fac7061dff14d78" }
 semantic_versioning = { url = "https://github.com/alire-project/semantic_versioning", commit = "2f23fc5f6b4855b836b599adf292fed9c0ed4144" }
 simple_logging = { url = "https://github.com/alire-project/simple_logging", commit = "3505dc645f3eef6799a486aae223d37e88cfc4d5" }
+si_units = { url = "https://github.com/mosteo/si_units", branch = "alire" }
 stopwatch = { url = "https://github.com/mosteo/stopwatch", commit = "f607a63b714f09bbf6126de9851cbc21cf8666c9" }
diff --git a/deps/si_units b/deps/si_units
index 39de6478b..9329d2591 160000
--- a/deps/si_units
+++ b/deps/si_units
@@ -1 +1 @@
-Subproject commit 39de6478ba6d63c24dd34dd7205a6ce2cb971703
+Subproject commit 9329d2591b82440ccc859a53f1380ac07ea4194d