diff --git a/src/data/writing_datatypes.jl b/src/data/writing_datatypes.jl
index f1fdc0b6..91c9f9f4 100644
--- a/src/data/writing_datatypes.jl
+++ b/src/data/writing_datatypes.jl
@@ -446,7 +446,7 @@ end
 
 function h5convert!(out::Pointers, ::DataTypeODR, f::JLDFile, T::DataType, wsession::JLDWriteSession)
     t = typename(T)
-    if T <: Function && Base.isgensym(nameof(T.instance))
+    if T <: Function && isgensym(nameof(T.instance))
         @warn LazyString("Attempting to store ", T, ".\n",
                          "JLD2 only stores functions by name.\n",
                          " This may not be useful for anonymous functions.")
diff --git a/src/julia_compat.jl b/src/julia_compat.jl
index f17e348e..a577bebb 100644
--- a/src/julia_compat.jl
+++ b/src/julia_compat.jl
@@ -28,4 +28,10 @@ end
     end
 else
     using Base: @nospecializeinfer
+end
+
+@static if VERSION < v"1.7.0"
+    isgensym(s::Symbol) = '#' in string(s)
+else
+    using Base: isgensym
 end
\ No newline at end of file