diff --git a/ext/SymbolicsLuxExt.jl b/ext/SymbolicsLuxExt.jl
index b4dfcab51..0086982c6 100644
--- a/ext/SymbolicsLuxExt.jl
+++ b/ext/SymbolicsLuxExt.jl
@@ -5,8 +5,10 @@ using Symbolics
 using Lux.LuxCore
 using Symbolics.SymbolicUtils
 
-function Lux.NilSizePropagation.recursively_nillify(x::SymbolicUtils.BasicSymbolic{<:Vector{<:Real}})
-    Lux.NilSizePropagation.recursively_nillify(Symbolics.wrap(x))
+@static if isdefined(Lux.NilSizePropagation, :recursively_nillify)
+    function Lux.NilSizePropagation.recursively_nillify(x::SymbolicUtils.BasicSymbolic{<:Vector{<:Real}})
+        Lux.NilSizePropagation.recursively_nillify(Symbolics.wrap(x))
+    end
 end
 
 @register_array_symbolic LuxCore.stateless_apply(