diff --git a/Formula/hdf5@1.8.rb b/Formula/hdf5@1.8.rb
index 598a36f548..cefc2b6e83 100644
--- a/Formula/hdf5@1.8.rb
+++ b/Formula/hdf5@1.8.rb
@@ -3,6 +3,7 @@ class Hdf5AT18 < Formula
   homepage "https://www.hdfgroup.org/HDF5"
   url "https://support.hdfgroup.org/ftp/HDF5/releases/hdf5-1.8/hdf5-1.8.21/src/hdf5-1.8.21.tar.bz2"
   sha256 "e5b1b1dee44a64b795a91c3321ab7196d9e0871fe50d42969761794e3899f40d"
+  revision 1
 
   bottle do
     sha256 "100e63ca57e49713edef20a610add098d9da6cf75f2e12146eb17a2625a6b6a3" => :mojave