diff --git a/src/services/Serialization.jl b/src/services/Serialization.jl
index b84dc096..3cf3723c 100644
--- a/src/services/Serialization.jl
+++ b/src/services/Serialization.jl
@@ -55,9 +55,21 @@ function parseVariableType(_typeString::AbstractString)
         typeString = _typeString
     end
 
-    all_subtypes = Dict(map(s -> nameof(s) => s, subtypes(InferenceVariable)))
+    split_typeSyms = Symbol.(split(typeString, "."))
 
-    subtype = get(all_subtypes, Symbol(split(typeString, ".")[end]), nothing)
+    subtype = nothing
+
+    if length(split_typeSyms) == 1
+        @warn "Module not found in variable '$typeString'." maxlog = 1
+        subtype = getfield(Main, split_typeSyms[1]) # no module specified, use Main
+    #FIXME interm fallback for backwards compatibility in IIFTypes and RoMETypes
+    elseif split_typeSyms[1] in Symbol.(values(Base.loaded_modules))
+        m = getfield(Main, split_typeSyms[1])
+        subtype = getfield(m, split_typeSyms[end])
+    else
+        @warn "Module not found in Main, using Main for type '$typeString'." maxlog = 1
+        subtype = getfield(Main, split_typeSyms[end])
+    end
 
     if isnothing(subtype)
         throw(SerializationError("Unable to deserialize type $(_typeString), not found"))
diff --git a/test/runtests.jl b/test/runtests.jl
index 434bd5ec..cdd7951b 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -63,10 +63,22 @@ end
 if get(ENV, "IIF_TEST", "true") == "true"
 
     # Switch to our upstream test branch.
+    #FIXME This is a temporary fix to use the develop branch of IIF.
+    # Pkg.add(PackageSpec(; name = "IncrementalInference", rev = "upstream/dfg_integration_test"))
+    # Pkg.add(PackageSpec(; name = "IncrementalInference", rev = "develop"))
     Pkg.add(
-        #FIXME This is a temporary fix to use the refactored factor branch.
-        # PackageSpec(; name = "IncrementalInference", rev = "upstream/dfg_integration_test"),
-        PackageSpec(; name = "IncrementalInference", rev = "develop"),
+        PackageSpec(;
+            url = "https://github.com/JuliaRobotics/IncrementalInference.jl.git",
+            subdir = "IncrementalInferenceTypes",
+            rev = "develop",
+        ),
+    )
+    Pkg.add(
+        PackageSpec(;
+            url = "https://github.com/JuliaRobotics/IncrementalInference.jl.git",
+            subdir = "IncrementalInference",
+            rev = "develop",
+        ),
     )
     @info "------------------------------------------------------------------------"
     @info "These tests are using IncrementalInference to do additional driver tests"