diff --git a/MozillaThunderbird.changes b/MozillaThunderbird.changes
index b6bfb12..4401ef9 100644
--- a/MozillaThunderbird.changes
+++ b/MozillaThunderbird.changes
@@ -1,3 +1,8 @@
+-------------------------------------------------------------------
+Thu Aug 20 08:57:15 UTC 2020 - Martin Liška <mliska@suse.cz>
+
+- Use memoryperjob constraint instead of %limit_build macro.
+
 -------------------------------------------------------------------
 Sat Aug  1 09:54:53 UTC 2020 - Andreas Stieger <andreas.stieger@gmx.de>
 
diff --git a/MozillaThunderbird.spec b/MozillaThunderbird.spec
index a4f5fc7..d976ce9 100644
--- a/MozillaThunderbird.spec
+++ b/MozillaThunderbird.spec
@@ -75,7 +75,6 @@ BuildRequires:  libXcomposite-devel
 BuildRequires:  libcurl-devel
 BuildRequires:  libidl-devel
 BuildRequires:  libnotify-devel
-BuildRequires:  memory-constraints
 BuildRequires:  mozilla-nspr-devel >= 4.21
 BuildRequires:  mozilla-nss-devel >= 3.44.4
 BuildRequires:  nasm >= 2.13
@@ -327,7 +326,6 @@ echo "export RUSTFLAGS=\"$RUSTFLAGS\""
 echo ""
 cat << EOF
 %else
-%limit_build -m 2000
 export MOZ_DEBUG_FLAGS="-pipe"
 cat << EOF > $MOZCONFIG
 %endif
diff --git a/_constraints b/_constraints
index 1b2d7b1..d13700f 100644
--- a/_constraints
+++ b/_constraints
@@ -7,6 +7,9 @@
     <memory>
       <size unit="G">9</size>
     </memory>
+    <memoryperjob>
+      <size unit="M">2000</size>
+    </memoryperjob>
   </hardware>
   <overwrite>
     <conditions>