diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,7 @@
+2018-10-27 Ivan Perez <ivan.perez@keera.co.uk>
+        * yampa-test.cabal: Version bump (0.1.1).
+        * src/: Fixes bug (#108).
+
 2018-10-21 Ivan Perez <ivan.perez@keera.co.uk>
         * Initial version.
 
diff --git a/src/FRP/Yampa/LTLFuture.hs b/src/FRP/Yampa/LTLFuture.hs
--- a/src/FRP/Yampa/LTLFuture.hs
+++ b/src/FRP/Yampa/LTLFuture.hs
@@ -42,6 +42,7 @@
 evalT (Prop sf)       = \stream -> firstSample $ fst $ evalSF sf stream
 evalT (And t1 t2)     = \stream -> evalT t1 stream && evalT t2 stream
 evalT (Or  t1 t2)     = \stream -> evalT t1 stream || evalT t2 stream
+evalT (Not t1)        = \stream -> not (evalT t1 stream)
 evalT (Implies t1 t2) = \stream -> not (evalT t1 stream) || evalT t2 stream
 evalT (Always  t1)    = \stream -> evalT t1 stream && evalT (Next (Always t1)) stream
 evalT (Eventually t1) = \stream -> case stream of
diff --git a/yampa-test.cabal b/yampa-test.cabal
--- a/yampa-test.cabal
+++ b/yampa-test.cabal
@@ -1,5 +1,5 @@
 name:                yampa-test
-version:             0.1.0.0
+version:             0.1.1
 synopsis:            Testing library for Yampa.
 description:
   Testing library for Yampa.