diff --git a/hostnames_allocator/Cargo.toml b/hostnames_allocator/Cargo.toml
index 5acb79a..ccf1231 100644
--- a/hostnames_allocator/Cargo.toml
+++ b/hostnames_allocator/Cargo.toml
@@ -17,7 +17,7 @@ lazy_static = "1.4.0"
 [dependencies.regex]
 version = "1.10.2"
 default-features = false
-features = ["std"]
+features = ["std", "unicode-perl"]
 
 [dev-dependencies]
 itertools = "0.11.0"