diff --git a/Project.toml b/Project.toml
index eeb55a9c..46b48b38 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "DelayDiffEq"
 uuid = "bcd4f6db-9728-5f36-b5f7-82caef46ccdb"
 authors = ["Chris Rackauckas <accounts@chrisrackauckas.com>"]
-version = "5.40.1"
+version = "5.40.2"
 
 [deps]
 ArrayInterface = "4fba245c-0d91-5ea0-9b3e-6abc04ee57a9"
diff --git a/src/DelayDiffEq.jl b/src/DelayDiffEq.jl
index e15ad4e0..545de08b 100644
--- a/src/DelayDiffEq.jl
+++ b/src/DelayDiffEq.jl
@@ -18,9 +18,14 @@ using DiffEqBase: AbstractDDEAlgorithm, AbstractDDEIntegrator, AbstractODEIntegr
 
 using DiffEqBase: @..
 
-using DiffEqBase: FastConvergence, Convergence, SlowConvergence, VerySlowConvergence,
-                  Divergence
-
+if isdefined(OrdinaryDiffEq, :FastConvergence)
+    using OrdinaryDiffEq: FastConvergence, Convergence, SlowConvergence,
+                          VerySlowConvergence,
+                          Divergence, AbstractNLSolverCache
+else
+    using DiffEqBase: FastConvergence, Convergence, SlowConvergence, VerySlowConvergence,
+                      Divergence, AbstractNLSolverCache
+end
 using OrdinaryDiffEq: RosenbrockMutableCache
 
 import SciMLBase
diff --git a/src/fpsolve/type.jl b/src/fpsolve/type.jl
index f94243cb..f5f0f2ad 100644
--- a/src/fpsolve/type.jl
+++ b/src/fpsolve/type.jl
@@ -1,5 +1,5 @@
 # solver
-mutable struct FPSolver{algType, iip, uTolType, C <: DiffEqBase.AbstractNLSolverCache} <:
+mutable struct FPSolver{algType, iip, uTolType, C <: AbstractNLSolverCache} <:
                OrdinaryDiffEq.AbstractNLSolver{algType, iip}
     alg::algType
     κ::uTolType
@@ -13,15 +13,15 @@ mutable struct FPSolver{algType, iip, uTolType, C <: DiffEqBase.AbstractNLSolver
 end
 
 # caches
-struct FPFunctionalCache{uType, uNoUnitsType} <: DiffEqBase.AbstractNLSolverCache
+struct FPFunctionalCache{uType, uNoUnitsType} <: AbstractNLSolverCache
     atmp::uNoUnitsType
     dz::uType
 end
 
-struct FPFunctionalConstantCache <: DiffEqBase.AbstractNLSolverCache end
+struct FPFunctionalConstantCache <: AbstractNLSolverCache end
 
 mutable struct FPAndersonCache{uType, uNoUnitsType, uEltypeNoUnits, D} <:
-               DiffEqBase.AbstractNLSolverCache
+               AbstractNLSolverCache
     atmp::uNoUnitsType
     dz::uType
     dzold::uType
@@ -36,7 +36,7 @@ mutable struct FPAndersonCache{uType, uNoUnitsType, uEltypeNoUnits, D} <:
 end
 
 mutable struct FPAndersonConstantCache{uType, uEltypeNoUnits, D} <:
-               DiffEqBase.AbstractNLSolverCache
+               AbstractNLSolverCache
     dz::uType
     dzold::uType
     z₊old::uType
diff --git a/src/utils.jl b/src/utils.jl
index dfc23e8d..70f07f7e 100644
--- a/src/utils.jl
+++ b/src/utils.jl
@@ -374,6 +374,6 @@ function unwrap_alg(integrator::DDEIntegrator, is_stiff)
     end
 end
 
-function DiffEqBase.nlsolve_f(integrator::DDEIntegrator)
-    DiffEqBase.nlsolve_f(integrator.f, unwrap_alg(integrator, true))
+function OrdinaryDiffEq.nlsolve_f(integrator::DDEIntegrator)
+    OrdinaryDiffEq.nlsolve_f(integrator.f, unwrap_alg(integrator, true))
 end