diff --git a/Project.toml b/Project.toml
index e74d616..71d5a61 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "CitableBase"
 uuid = "d6f014bd-995c-41bd-9893-703339864534"
 authors = ["Neel Smith <dnsmith.neel@gmail.com>"]
-version = "1.2.1"
+version = "1.2.2"
 
 [deps]
 DocStringExtensions = "ffbed154-4ef7-542d-bbb7-c09d3a79fcae"
diff --git a/src/versions.jl b/src/versions.jl
index bf99581..fc68779 100644
--- a/src/versions.jl
+++ b/src/versions.jl
@@ -1,7 +1,7 @@
 """Catch-all function for `dropversion` method.
 $(SIGNATURES)
 """
-function dropversion(u::Urn)
+function dropversion(u::T) where {T <: Urn}
     msg = string("dropversion not implemented for ", typeof(u))
     @warn(msg)
     nothing
@@ -10,7 +10,7 @@ end
 """Catch-all function for `addversion` method.
 $(SIGNATURES)
 """
-function addversion(u::Urn, s::AbstractString)
+function addversion(u::T, s::AbstractString) where {T <: Urn}
     msg = string("addversion not implemented for ", typeof(u))
     @warn(msg)
     nothing
diff --git a/test/test_functiondefs.jl b/test/test_functiondefs.jl
index fbbbb96..4e0306a 100644
--- a/test/test_functiondefs.jl
+++ b/test/test_functiondefs.jl
@@ -19,4 +19,21 @@ end
     u = FakeUrn("urn:fake:id.subid")
     @test isnothing(dropversion(u))
     @test isnothing(addversion(u, "versionid"))
+end
+
+
+
+@testset "Test ovveride validurn" begin
+    struct FakeUrn <: Urn
+        urn::AbstractString
+    end
+    function dropversion(u::FakeUrn)
+        "Success"
+    end
+    function addversion(u::FakeUrn, s)
+        "Success adding $s"
+    end
+    u = FakeUrn("urn:fake:id.subid")
+    @test dropversion(u) == "Success"
+    @test addversion(u, "versionid") == "Success adding versionid"
 end
\ No newline at end of file