diff --git a/src/taoensso/nippy.clj b/src/taoensso/nippy.clj
index 205df1d..45fa572 100644
--- a/src/taoensso/nippy.clj
+++ b/src/taoensso/nippy.clj
@@ -352,7 +352,7 @@
 ;; See also `nippy.tools` ns for further dynamic config support
 
 ;; For back compatibility (incl. Timbre's Carmine appender)
-(enc/defonce ^:dynamic ^:no-doc ^:deprecated *final-freeze-fallback* "Prefer `*freeze-fallback`.")
+(enc/defonce ^:dynamic ^:no-doc ^:deprecated *final-freeze-fallback* "Prefer `*freeze-fallback`." nil)
 (enc/defonce ^:dynamic                             *freeze-fallback*
   "Controls Nippy's behaviour when trying to freeze an item for which Nippy
   doesn't currently have a native freeze/thaw implementation.
diff --git a/test/taoensso/nippy_tests.clj b/test/taoensso/nippy_tests.clj
index 9bb9d9c..fe5e664 100644
--- a/test/taoensso/nippy_tests.clj
+++ b/test/taoensso/nippy_tests.clj
@@ -94,6 +94,8 @@
         (let [n    range-uint+]                          (= (thaw (freeze n)) n))
         (let [n (- range-uint+)]                         (= (thaw (freeze n)) n))]))
 
+   (is (enc/throws? :ex-info "Unfreezable type" (nippy/freeze (fn []))))
+
    (is (gen-test 1600 [gen-data] (= gen-data (thaw (freeze gen-data)))) "Generative")])
 
 ;;;; Custom types & records