diff --git a/docs/Project.toml b/docs/Project.toml
index 4b65c921..1d95d904 100644
--- a/docs/Project.toml
+++ b/docs/Project.toml
@@ -7,6 +7,7 @@ IfElse = "615f187c-cbe4-4ef1-ba3b-2fcf58d6d173"
 ModelingToolkit = "961ee093-0014-501f-94e3-6117800e7a78"
 ModelingToolkitStandardLibrary = "16a59e39-deab-5bd0-87e4-056b12336739"
 OrdinaryDiffEq = "1dea7af3-3e70-54e6-95c3-0bf5283fa5ed"
+OrdinaryDiffEqSDIRK = "2d112036-d095-4a1e-ab9a-08536f3ecdbf"
 Plots = "91a5bcdd-55d7-5caf-9e0b-520d859cae80"
 SciCompDSL = "91a8cdf1-4ca6-467b-a780-87fda3fff15e"
 
@@ -19,5 +20,6 @@ IfElse = "0.1"
 ModelingToolkit = "11"
 ModelingToolkitStandardLibrary = "2.28.0"
 OrdinaryDiffEq = "6, 7"
+OrdinaryDiffEqSDIRK = "1, 2"
 Plots = "1.36"
 SciCompDSL = "1"
diff --git a/docs/src/connectors/connections.md b/docs/src/connectors/connections.md
index 3af6451c..1e079d46 100644
--- a/docs/src/connectors/connections.md
+++ b/docs/src/connectors/connections.md
@@ -191,7 +191,8 @@ nothing # hide
 As can be seen, we get exactly the same result.  The only difference here is that we are solving an extra equation, which allows us to plot the body position as well.
 
 ```@example connections
-prob = ODEProblem(sys, [], (0, 10.0), fully_determined = true)
+prob = ODEProblem(
+    sys, [], (0, 10.0); initialization_eqs = [sys.body.s ~ 0, sys.body.v ~ 1])
 sol_p = solve(prob)
 
 p1 = plot(sol_p, idxs = [body.v])
diff --git a/docs/src/tutorials/custom_component.md b/docs/src/tutorials/custom_component.md
index 5d277b39..6192d6f8 100644
--- a/docs/src/tutorials/custom_component.md
+++ b/docs/src/tutorials/custom_component.md
@@ -36,7 +36,7 @@ this can almost be directly translated to the syntax of `ModelingToolkit`.
 
 ```@example components
 @mtkmodel NonlinearResistor begin
-    @extend OnePort()
+    @extend v, i = oneport = OnePort()
     @parameters begin
         Ga
         Gb
@@ -58,7 +58,7 @@ nothing # hide
 Since the non-linear resistor is essentially a standard electrical component with two ports, we can extend from the `OnePort` component of the library.
 
 ```julia
-@extend OnePort()
+@extend v, i = oneport = OnePort()
 ```
 
 This extends `OnePort` and unpacks `v` and `i` variables.
diff --git a/src/Blocks/Blocks.jl b/src/Blocks/Blocks.jl
index 2670de16..e07ec5e8 100644
--- a/src/Blocks/Blocks.jl
+++ b/src/Blocks/Blocks.jl
@@ -5,6 +5,7 @@ module Blocks
 using ModelingToolkitBase: ModelingToolkitBase, @component, @connector, @named,
     @parameters, @unpack, System, compose, connect, extend,
     getdefault, t_nounits as t, D_nounits as D
+using SymbolicUtils: @syms, symtype
 using Symbolics: Symbolics, @register_symbolic, @variables, Differential, Equation
 import Base: ifelse
 import ..@symcheck
diff --git a/src/Blocks/sources.jl b/src/Blocks/sources.jl
index 9e282d86..e7463a5d 100644
--- a/src/Blocks/sources.jl
+++ b/src/Blocks/sources.jl
@@ -864,7 +864,15 @@ end
 
 Base.nameof(::CachedInterpolation) = :CachedInterpolation
 
-@register_symbolic (f::CachedInterpolation)(u::AbstractArray, x::AbstractArray, args::Tuple)
+const _INTERPOLATOR_SYMTYPE = let
+    @syms interpolator(::Real)::Real
+    symtype(interpolator)
+end
+
+# Calling the builder returns the interpolation function, not an interpolated scalar.
+@register_symbolic (f::CachedInterpolation)(
+    u::AbstractArray, x::AbstractArray, args::Tuple
+)::_INTERPOLATOR_SYMTYPE
 
 """
     ParametrizedInterpolation(interp_type, u, x, args...; name, t = ModelingToolkitBase.t_nounits)
diff --git a/test/sources.jl b/test/sources.jl
index 31efad4d..780830e3 100644
--- a/test/sources.jl
+++ b/test/sources.jl
@@ -14,6 +14,7 @@ using SymbolicIndexingInterface
 using SciMLStructures: SciMLStructures, Tunable
 using ForwardDiff
 using ADTypes
+using SymbolicUtils: symtype
 
 @testset "Constant" begin
     @named src = Constant(k = 2)
@@ -650,6 +651,9 @@ end
 
     @testset "LinearInterpolation" begin
         @named i = ParametrizedInterpolation(LinearInterpolation, u, x)
+        interpolator = only(values(bindings(i)))
+        @test symtype(interpolator(0.0)) === Real
+
         eqs = [i.input.u ~ t, D(y) ~ i.output.u]
 
         @named model = System(eqs, t, systems = [i])