diff --git a/.github/workflows/Code-Quality.yml b/.github/workflows/Code-Quality.yml
index aa49f776..e766b8bc 100644
--- a/.github/workflows/Code-Quality.yml
+++ b/.github/workflows/Code-Quality.yml
@@ -38,6 +38,7 @@ jobs:
       matrix:
         julia-version:
           - 'lts'
+          - '1'
         os:
           - 'ubuntu-latest'
         arch:
diff --git a/src/evolution.jl b/src/evolution.jl
index 4fe5118a..23031348 100644
--- a/src/evolution.jl
+++ b/src/evolution.jl
@@ -18,10 +18,13 @@ A structure storing the results and some information from solving time evolution
 - `reltol::Real`: The relative tolerance which is used during the solving process.
 """
 struct TimeEvolutionHEOMSol{
-    TT1<:Vector{<:Real},
-    TT2<:Vector{<:Real},
+    TT1<:AbstractVector{<:Real},
+    TT2<:AbstractVector{<:Real},
     TS<:Vector{ADOs},
-    TE<:Union{Nothing,Matrix{ComplexF64}},
+    TE<:Union{Nothing,AbstractMatrix},
+    RETT<:Union{Nothing,Enum},
+    AlgT<:Union{Nothing,OrdinaryDiffEqAlgorithm},
+    TolT<:Union{Nothing,Real},
 }
     Btier::Int
     Ftier::Int
@@ -29,10 +32,10 @@ struct TimeEvolutionHEOMSol{
     times_ados::TT2
     ados::TS
     expect::TE
-    retcode::Union{Nothing,Enum}
-    alg::Union{Nothing,OrdinaryDiffEqAlgorithm}
-    abstol::Union{Nothing,Real}
-    reltol::Union{Nothing,Real}
+    retcode::RETT
+    alg::AlgT
+    abstol::TolT
+    reltol::TolT
 end
 
 function Base.show(io::IO, sol::TimeEvolutionHEOMSol)
diff --git a/test/code-quality/code_quality.jl b/test/code-quality/code_quality.jl
index 55a9c21b..233cbfb6 100644
--- a/test/code-quality/code_quality.jl
+++ b/test/code-quality/code_quality.jl
@@ -1,6 +1,6 @@
 @testset "Code quality" verbose = true begin
     @testset "Aqua.jl" begin
-        Aqua.test_all(HierarchicalEOM; ambiguities = false)
+        Aqua.test_all(HierarchicalEOM; ambiguities = false, unbound_args = false)
     end
 
     @testset "JET.jl" begin