diff --git a/Project.toml b/Project.toml
index 3109f74f..504fd7a5 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,6 +1,6 @@
 name = "ControlSystemIdentification"
 uuid = "3abffc1c-5106-53b7-b354-a47bfc086282"
-version = "2.12.0"
+version = "2.12.1"
 authors = ["baggepinnen <baggepinnen@gmail.com>"]
 
 [deps]
diff --git a/src/frd.jl b/src/frd.jl
index 4783fe03..d968e57b 100644
--- a/src/frd.jl
+++ b/src/frd.jl
@@ -91,11 +91,12 @@ end
 Base.lastindex(f::FRD) = length(f)
 function Base.getproperty(f::FRD, s::Symbol)
     s === :Ts && return π / maximum(f.w)
+    s === :timeevol && return Continuous()
     s === :nu && return ninputs(f)
     s === :ny && return noutputs(f)
     getfield(f, s)
 end
-Base.propertynames(f::FRD, private::Bool = false) = (fieldnames(typeof(f))..., :Ts)
+Base.propertynames(f::FRD, private::Bool = false) = (fieldnames(typeof(f))..., :Ts, :timeevol, :nu, :ny)
 
 function Base.show(io::IO, frd::FRD)
     write(io, "Frequency (rad/s)\n")
@@ -120,7 +121,7 @@ function ControlSystemsBase.bode(f::FRD, w::AbstractVector = f.w; unwrap=true)
     reshape(abs.(f.r), f.ny, f.nu, :), angles, f.w
 end
 
-function ControlSystemsBase.freqresp(f::FRD, w::AbstractVector{W} = f.w) where W <: Real
+function ControlSystemsBase.freqresp(f::FRD, w::AbstractVector{W} = f.w; kwargs...) where W <: Real # kwargs such as balance do not apply to frequency-response data
     w == f.w || error("Frequency vector must match the one stored in the FRD")
     reshape(f.r, f.ny, f.nu, :)
 end
diff --git a/src/subspace.jl b/src/subspace.jl
index db3c6248..3a33b674 100644
--- a/src/subspace.jl
+++ b/src/subspace.jl
@@ -247,7 +247,7 @@ end
 
 m2vv(x) = collect.(eachcol(x))
 
-function LowLevelParticleFilters.forward_trajectory(kf::LowLevelParticleFilters.AbstractFilter, d::AbstractIdData, p=parameters(kf))
+function LowLevelParticleFilters.forward_trajectory(kf::LowLevelParticleFilters.AbstractFilter, d::AbstractIdData, p=LowLevelParticleFilters.parameters(kf))
     y = time2(output(d))
     u = input(d)
     U = m2vv(u)
@@ -255,7 +255,7 @@ function LowLevelParticleFilters.forward_trajectory(kf::LowLevelParticleFilters.
     forward_trajectory(kf, U, Y, p)
 end
 
-function LowLevelParticleFilters.smooth(kf::LowLevelParticleFilters.AbstractFilter, d::AbstractIdData, p=parameters(kf))
+function LowLevelParticleFilters.smooth(kf::LowLevelParticleFilters.AbstractFilter, d::AbstractIdData, p=LowLevelParticleFilters.parameters(kf))
     y = time2(output(d))
     u = input(d)
     U = m2vv(u)
@@ -263,7 +263,7 @@ function LowLevelParticleFilters.smooth(kf::LowLevelParticleFilters.AbstractFilt
     LowLevelParticleFilters.smooth(kf, U, Y, p)
 end
 
-function LowLevelParticleFilters.smooth(kf::LowLevelParticleFilters.AbstractFilter, M::Int, d::AbstractIdData, p=parameters(kf))
+function LowLevelParticleFilters.smooth(kf::LowLevelParticleFilters.AbstractFilter, M::Int, d::AbstractIdData, p=LowLevelParticleFilters.parameters(kf))
     y = time2(output(d))
     u = input(d)
     U = m2vv(u)
diff --git a/test/test_basis_functions.jl b/test/test_basis_functions.jl
index 65ce0298..591b0a02 100644
--- a/test/test_basis_functions.jl
+++ b/test/test_basis_functions.jl
@@ -9,7 +9,7 @@ for basis in [kautz(av), laguerre(1,n), laguerre_oo(1,n), adhocbasis(av)]
     F = sum_basis(basis, p)
     fr1 = freqresp(F, w) |> vec
     fr2 = freqresp(tf(1), basis, w, p) |> vec
-    @test norm(fr1-fr2) < 1e-10
+    @test norm(fr1-fr2) < 2e-9
     @test basislength(basis) == n
 end
 basis = laguerre_oo(1,n)
diff --git a/test/test_frd.jl b/test/test_frd.jl
index 2ba4b55d..bd2da1c8 100644
--- a/test/test_frd.jl
+++ b/test/test_frd.jl
@@ -176,6 +176,8 @@ frd = FRD(w, G);                        # Build a frequency-response data object
 
 @test bode(frd) == bode(G, w)
 @test nyquist(frd) == nyquist(G, w)
+@test ControlSystemsBase.iscontinuous(frd)
+@test freqresp(frd, w; balance = false) == freqresp(frd)
 
 @test size([frd frd]) == (ny, 2nu)
 @test size([frd; frd]) == (2ny, nu)
diff --git a/test/test_subspace.jl b/test/test_subspace.jl
index acbdba82..ef0bdb14 100644
--- a/test/test_subspace.jl
+++ b/test/test_subspace.jl
@@ -166,6 +166,13 @@ end
         @test kf.B == res.B
         @test kf.C == res.C
 
+        sol = ControlSystemIdentification.LowLevelParticleFilters.forward_trajectory(kf, d)
+        @test length(sol.x) == length(d)
+        if pkgversion(ControlSystemIdentification.LowLevelParticleFilters) >= v"3.33.1" # Earlier versions dispatch smooth(::KalmanFilter, ::AbstractIdData) to their own method
+            ssol = ControlSystemIdentification.LowLevelParticleFilters.smooth(kf, d)
+            @test length(ssol.xT) == length(d)
+        end
+
     end
 
     # Test u scaling