diff --git a/Project.toml b/Project.toml
index f771bc4..6e53b21 100644
--- a/Project.toml
+++ b/Project.toml
@@ -24,7 +24,7 @@ LabelledArrays = "1"
 LinearAlgebra = "1"
 Optimization = "3"
 OptimizationOptimJL = "0.1"
-OrdinaryDiffEq = "6"
+OrdinaryDiffEq = "6.65"
 Pkg = "1"
 Random = "1"
 RecursiveArrayTools = "2, 3"
diff --git a/test/core_nesteddual.jl b/test/core_nesteddual.jl
index 0af489e..abde832 100644
--- a/test/core_nesteddual.jl
+++ b/test/core_nesteddual.jl
@@ -102,8 +102,6 @@ function objfun(x, prob, realsol, cache)
     return ofv
 end
 
-fn(x, p) = objfun(x, p[1], p[2], p[3])
-
 optfun = OptimizationFunction(fn, Optimization.AutoForwardDiff())
 optprob = OptimizationProblem(optfun, zeros(length(coeffs)), (prob, realsol, cache))
 newtonsol2 = solve(optprob, Newton())
diff --git a/test/core_odes.jl b/test/core_odes.jl
index 5639cb0..8653a7d 100644
--- a/test/core_odes.jl
+++ b/test/core_odes.jl
@@ -2,9 +2,6 @@ using LinearAlgebra,
     OrdinaryDiffEq, Test, PreallocationTools, LabelledArrays,
     RecursiveArrayTools
 
-# upstream
-OrdinaryDiffEq.DiffEqBase.anyeltypedual(x::FixedSizeDiffCache, counter = 0) = Any
-
 #Base array
 function foo(du, u, (A, tmp), t)
     tmp = get_tmp(tmp, u)