diff --git a/Project.toml b/Project.toml
index 988d9f54a..0236e0328 100644
--- a/Project.toml
+++ b/Project.toml
@@ -61,7 +61,7 @@ LinearAlgebra = "1"
 MatrixEquations = "2"
 Octavian = "0.3.17"
 OrdinaryDiffEq = "6.52"
-PSDMatrices = "0.4.7"
+PSDMatrices = "0.5.0"
 PrecompileTools = "1"
 Printf = "1"
 Random = "1"
diff --git a/src/ProbNumDiffEq.jl b/src/ProbNumDiffEq.jl
index 57bda4e25..1bd5cce8f 100644
--- a/src/ProbNumDiffEq.jl
+++ b/src/ProbNumDiffEq.jl
@@ -39,7 +39,6 @@ using DiffEqCallbacks
 
 @reexport using PSDMatrices
 import PSDMatrices: X_A_Xt, X_A_Xt!, unfactorize
-X_A_Xt(A, X) = X * A * X'
 
 stack(x) = copy(reduce(hcat, x)')
 vecvec2mat(x) = reduce(hcat, x)'
diff --git a/src/kronecker.jl b/src/kronecker.jl
index cb3459179..b7edd0093 100644
--- a/src/kronecker.jl
+++ b/src/kronecker.jl
@@ -1,4 +1,3 @@
-copy(K::Kronecker.KroneckerProduct) = Kronecker.KroneckerProduct(copy(K.A), copy(K.B))
 @doc raw"""
     IsometricKroneckerProduct(left_factor_dim::Int64, left_factor::AbstractMatrix)
 
diff --git a/test/runtests.jl b/test/runtests.jl
index f346ac675..12ad4551a 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -143,7 +143,6 @@ const GROUP = get(ENV, "GROUP", "All")
             Aqua.test_all(
                 ProbNumDiffEq,
                 ambiguities=false,
-                piracies=false,
             )
         end
         @timedtestset "Code linting (JET.jl)" begin