diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index f1c07345901..d5c4abf01e7 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -10,6 +10,3 @@ updates:
       all-github-actions:
         patterns:
           - "*"
-    ignore:
-      - dependency-name: "julia-actions/julia-downgrade-compat"
-        versions: [ ">=2.0.0" ]
diff --git a/.github/workflows/Downgrade.yml b/.github/workflows/Downgrade.yml
index fc13bc61d05..f3e50aa5d36 100644
--- a/.github/workflows/Downgrade.yml
+++ b/.github/workflows/Downgrade.yml
@@ -66,7 +66,8 @@ jobs:
           # - performance_specializations_part1
           # - performance_specializations_part2
           # - mpi
-          - threaded
+          # - threaded
+          - downgrade
     steps:
       - uses: actions/checkout@v6
       - uses: julia-actions/setup-julia@v2
@@ -75,17 +76,22 @@ jobs:
           arch: ${{ matrix.arch }}
       - run: julia -e 'using InteractiveUtils; versioninfo(verbose=true)'
       - uses: julia-actions/cache@v2
-      - uses: julia-actions/julia-downgrade-compat@v1
+      - uses: julia-actions/julia-downgrade-compat@v2
         with:
           skip: LinearAlgebra,Printf,SparseArrays,UUIDs,DelimitedFiles,Test,Downloads,Random
           projects: ., test
-      - uses: julia-actions/julia-buildpkg@v1
+          mode: forcedeps
+      # We run the tests manually instead of using julia-action/julia-builpkg and julia-action/julia-runtest or `Pkg.test`
+      # because otherwise the downgraded Manifest.toml is not used in the tests under julia <v1.12
+      # see also https://github.com/julia-actions/julia-downgrade-compat/blob/00f940b7be2b50389571ed016d603be561649103/README.md#L89
+      - name: Run tests
+        run: |
+          julia --project=test --color=yes -e '
+            import Pkg
+            Pkg.develop(Pkg.PackageSpec(path=pwd()))
+            Pkg.instantiate()
+            Pkg.status(; mode = Pkg.PKGMODE_MANIFEST)
+            include("test/runtests.jl")
+          '
         env:
-          PYTHON: ''
-      - name: Run tests without coverage
-        uses: julia-actions/julia-runtest@v1
-        with:
-          coverage: false
-        env:
-          PYTHON: ''
           TRIXI_TEST: ${{ matrix.trixi_test }}
diff --git a/Project.toml b/Project.toml
index ee7b35463cb..8eca8d18b8f 100644
--- a/Project.toml
+++ b/Project.toml
@@ -73,7 +73,7 @@ Accessors = "0.1.36"
 Adapt = "4.1"
 CUDA = "5.8.2"
 CodeTracking = "1.0.5, 2, 3"
-ConstructionBase = "1.5"
+ConstructionBase = "1.5.8"
 Convex = "0.16"
 DataStructures = "0.18.15, 0.19"
 DelimitedFiles = "1"
@@ -84,7 +84,7 @@ ECOS = "1.1.2"
 EllipsisNotation = "1.0"
 FillArrays = "1.9"
 ForwardDiff = "0.10.36, 1"
-HDF5 = "0.16.10, 0.17"
+HDF5 = "0.17"
 KernelAbstractions = "0.9.36"
 LinearAlgebra = "1"
 LinearMaps = "2.7, 3.0"
@@ -97,12 +97,12 @@ Octavian = "0.3.28"
 OffsetArrays = "1.13"
 P4est = "0.4.12"
 Polyester = "=0.7.16, 0.7.18"
-PrecompileTools = "1.2"
-Preferences = "1.4"
+PrecompileTools = "1.2.1"
+Preferences = "1.4.3"
 Printf = "1"
 RecipesBase = "1.3.4"
 RecursiveArrayTools = "3.31.1"
-Reexport = "1.2"
+Reexport = "1.2.2"
 Requires = "1.3"
 SciMLBase = "2.92.0"
 SimpleUnPack = "1.1"
@@ -112,7 +112,7 @@ StableRNGs = "1.0.2"
 StartUpDG = "1.1.5"
 Static = "1.1.1"
 StaticArrayInterface = "1.5.1"
-StaticArrays = "1.9"
+StaticArrays = "1.9.8"
 StrideArrays = "0.1.29"
 StructArrays = "0.6.20, 0.7"
 SummationByPartsOperators = "0.5.52"
diff --git a/test/runtests.jl b/test/runtests.jl
index 8b524a09df8..742d832bf31 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -22,7 +22,7 @@ const TRIXI_NTHREADS = clamp(Sys.CPU_THREADS, 2, 3)
 
         # We provide a `--heap-size-hint` to avoid/reduce out-of-memory errors during CI testing
         mpiexec() do cmd
-            run(`$cmd -n $TRIXI_MPI_NPROCS $(Base.julia_cmd()) --threads=1 --check-bounds=yes --heap-size-hint=0.5G $(abspath("test_mpi.jl"))`)
+            run(`$cmd -n $TRIXI_MPI_NPROCS $(Base.julia_cmd()) --threads=1 --check-bounds=yes --heap-size-hint=0.5G $(joinpath(@__DIR__, "test_mpi.jl"))`)
             return nothing
         end
     end
@@ -34,87 +34,95 @@ const TRIXI_NTHREADS = clamp(Sys.CPU_THREADS, 2, 3)
         # cf. https://github.com/JuliaParallel/MPI.jl/pull/391
         @test true
 
-        run(`$(Base.julia_cmd()) --threads=$TRIXI_NTHREADS --check-bounds=yes --code-coverage=none $(abspath("test_threaded.jl"))`)
+        run(`$(Base.julia_cmd()) --threads=$TRIXI_NTHREADS --check-bounds=yes --code-coverage=none $(joinpath(@__DIR__, "test_threaded.jl"))`)
+    end
+
+    # Downgrade CI currently has issues with running julia processes via `run`, see
+    # https://github.com/trixi-framework/Trixi.jl/pull/2507#issuecomment-3990318366
+    # So we run test_threaded.jl serially.
+    # For `TRIXI_TEST = "all"`, test_threaded.jl is already covered by the threaded run, so we don't need to run it again.
+    @time if TRIXI_TEST == "downgrade"
+        include(joinpath(@__DIR__, "test_threaded.jl"))
     end
 
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "tree_part1"
-        include("test_tree_1d.jl")
-        include("test_tree_2d_part1.jl")
+        include(joinpath(@__DIR__, "test_tree_1d.jl"))
+        include(joinpath(@__DIR__, "test_tree_2d_part1.jl"))
     end
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "tree_part2"
-        include("test_tree_2d_part2.jl")
+        include(joinpath(@__DIR__, "test_tree_2d_part2.jl"))
     end
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "tree_part3"
-        include("test_tree_2d_part3.jl")
+        include(joinpath(@__DIR__, "test_tree_2d_part3.jl"))
     end
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "tree_part4"
-        include("test_tree_3d_part1.jl")
+        include(joinpath(@__DIR__, "test_tree_3d_part1.jl"))
     end
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "tree_part5"
-        include("test_tree_3d_part2.jl")
+        include(joinpath(@__DIR__, "test_tree_3d_part2.jl"))
     end
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "tree_part6"
-        include("test_tree_3d_part3.jl")
+        include(joinpath(@__DIR__, "test_tree_3d_part3.jl"))
     end
 
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "structured"
-        include("test_structured_1d.jl")
-        include("test_structured_2d.jl")
-        include("test_structured_3d.jl")
+        include(joinpath(@__DIR__, "test_structured_1d.jl"))
+        include(joinpath(@__DIR__, "test_structured_2d.jl"))
+        include(joinpath(@__DIR__, "test_structured_3d.jl"))
     end
 
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "p4est_part1"
-        include("test_p4est_2d.jl")
+        include(joinpath(@__DIR__, "test_p4est_2d.jl"))
     end
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "p4est_part2"
-        include("test_p4est_3d.jl")
+        include(joinpath(@__DIR__, "test_p4est_3d.jl"))
     end
 
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "t8code_part1"
-        include("test_t8code_2d.jl")
+        include(joinpath(@__DIR__, "test_t8code_2d.jl"))
     end
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "t8code_part2"
-        include("test_t8code_3d.jl")
+        include(joinpath(@__DIR__, "test_t8code_3d.jl"))
     end
 
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "unstructured_dgmulti"
-        include("test_unstructured_2d.jl")
-        include("test_dgmulti_1d.jl")
-        include("test_dgmulti_2d.jl")
-        include("test_dgmulti_3d.jl")
+        include(joinpath(@__DIR__, "test_unstructured_2d.jl"))
+        include(joinpath(@__DIR__, "test_dgmulti_1d.jl"))
+        include(joinpath(@__DIR__, "test_dgmulti_2d.jl"))
+        include(joinpath(@__DIR__, "test_dgmulti_3d.jl"))
     end
 
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "parabolic_part1"
-        include("test_parabolic_1d.jl")
-        include("test_parabolic_2d.jl")
+        include(joinpath(@__DIR__, "test_parabolic_1d.jl"))
+        include(joinpath(@__DIR__, "test_parabolic_2d.jl"))
     end
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "parabolic_part2"
-        include("test_parabolic_3d.jl")
+        include(joinpath(@__DIR__, "test_parabolic_3d.jl"))
     end
 
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "misc_part1"
-        include("test_unit.jl")
-        include("test_type.jl")
-        include("test_visualization.jl")
+        include(joinpath(@__DIR__, "test_unit.jl"))
+        include(joinpath(@__DIR__, "test_type.jl"))
+        include(joinpath(@__DIR__, "test_visualization.jl"))
     end
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "misc_part2"
-        include("test_special_elixirs.jl")
-        include("test_aqua.jl")
+        include(joinpath(@__DIR__, "test_special_elixirs.jl"))
+        include(joinpath(@__DIR__, "test_aqua.jl"))
     end
 
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "performance_specializations"
-        include("test_performance_specializations_2d.jl")
-        include("test_performance_specializations_3d.jl")
+        include(joinpath(@__DIR__, "test_performance_specializations_2d.jl"))
+        include(joinpath(@__DIR__, "test_performance_specializations_3d.jl"))
     end
 
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "paper_self_gravitating_gas_dynamics"
-        include("test_paper_self_gravitating_gas_dynamics.jl")
+        include(joinpath(@__DIR__, "test_paper_self_gravitating_gas_dynamics.jl"))
     end
 
     @time if TRIXI_TEST == "all" || TRIXI_TEST == "CUDA"
         import CUDA
         if CUDA.functional()
-            include("test_cuda.jl")
+            include(joinpath(@__DIR__, "test_cuda.jl"))
         else
             @warn "Unable to run CUDA tests on this machine"
         end