diff --git a/Project.toml b/Project.toml
index cb9fff5..f7c55b8 100644
--- a/Project.toml
+++ b/Project.toml
@@ -11,7 +11,7 @@ RuntimeGeneratedFunctions = "7e49a35a-f44a-4d26-94aa-eba1b4ca6b47"
 Symbolics = "0c5d862f-8b57-4792-8d23-62f2024744c7"
 
 [compat]
-GeometricBase = "0.8, 0.9"
+GeometricBase = "0.9"
 GeometricEquations = "0.12, 0.13, 0.14"
 RuntimeGeneratedFunctions = "0.5"
 Symbolics = "5"
diff --git a/src/EulerLagrange.jl b/src/EulerLagrange.jl
index 6a5ddc4..439e320 100644
--- a/src/EulerLagrange.jl
+++ b/src/EulerLagrange.jl
@@ -1,6 +1,6 @@
 module EulerLagrange
 
-    using GeometricBase: NullParameters, State
+    using GeometricBase: NullParameters, StateVariable
     using RuntimeGeneratedFunctions
     using Symbolics
     using Symbolics: ArrayLike, FnType, Sym
diff --git a/src/hamiltonian.jl b/src/hamiltonian.jl
index 994233b..bbd7835 100644
--- a/src/hamiltonian.jl
+++ b/src/hamiltonian.jl
@@ -113,7 +113,7 @@ function HODEProblem(lsys::HamiltonianSystem, tspan::Tuple, tstep::Real, ics::Na
     HODEProblem(eqs.v, eqs.f, eqs.H, tspan, tstep, ics)
 end
 
-function HODEProblem(lsys::HamiltonianSystem, tspan::Tuple, tstep::Real, q₀::State, p₀::State)
+function HODEProblem(lsys::HamiltonianSystem, tspan::Tuple, tstep::Real, q₀::StateVariable, p₀::StateVariable)
     ics = (q = q₀, p = p₀)
     HODEProblem(lsys, tspan, tstep, ics)
 end
diff --git a/src/lagrangian.jl b/src/lagrangian.jl
index 40ac5b2..0ffdf7f 100644
--- a/src/lagrangian.jl
+++ b/src/lagrangian.jl
@@ -181,7 +181,7 @@ function LODEProblem(lsys::LagrangianSystem, tspan::Tuple, tstep::Real, ics::Nam
     LODEProblem(eqs.ϑ, eqs.f, eqs.g, eqs.ω, eqs.L, tspan, tstep, ics; v̄ = eqs.v̄, f̄ = eqs.f̄)
 end
 
-function LODEProblem(lsys::LagrangianSystem, tspan::Tuple, tstep::Real, q₀::State, p₀::State, λ₀::State = zero(q₀))
+function LODEProblem(lsys::LagrangianSystem, tspan::Tuple, tstep::Real, q₀::StateVariable, p₀::StateVariable, λ₀::StateVariable = zero(q₀))
     ics = (q = q₀, p = p₀, λ = λ₀)
     LODEProblem(lsys, tspan, tstep, ics)
 end