diff --git a/lib/OrdinaryDiffEqFIRK/src/alg_utils.jl b/lib/OrdinaryDiffEqFIRK/src/alg_utils.jl
index 46dfcb8206..692a86bb88 100644
--- a/lib/OrdinaryDiffEqFIRK/src/alg_utils.jl
+++ b/lib/OrdinaryDiffEqFIRK/src/alg_utils.jl
@@ -10,4 +10,4 @@ isfirk(alg::RadauIIA9) = true
 
 alg_adaptive_order(alg::RadauIIA3) = 1
 alg_adaptive_order(alg::RadauIIA5) = 3
-alg_adaptive_order(alg::RadauIIA9) = 7
+alg_adaptive_order(alg::RadauIIA9) = 5