diff --git a/var/spack/repos/builtin/packages/abacus/package.py b/var/spack/repos/builtin/packages/abacus/package.py
index 68ee2f4894c..ccf89f82b8d 100644
--- a/var/spack/repos/builtin/packages/abacus/package.py
+++ b/var/spack/repos/builtin/packages/abacus/package.py
@@ -65,7 +65,7 @@ def edit(self, spec, prefix):
                 spec["fftw"].prefix,
                 spec["elpa"].prefix,
                 inc_var,
-                "{0}".format(spec["elpa"].version),
+                f"{spec['elpa'].version}",
                 spec["cereal"].prefix,
             )
         )