diff --git a/DESCRIPTION b/DESCRIPTION
index c138f323f364b420c935397e958c25ffdbc807b1..2cb2cd9271907ac1538c0e5e4eb8575e4f84b7ef 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: sybil
 Type: Package
 Title: Efficient Constrained Based Modelling in R
-Version: 1.3.2
+Version: 1.3.3
 Date: 2015-11-16
 Authors@R: c(
 	     person(c("C.", "Jonathan"), "Fritzemeier", role = c("cre", "ctb"), email = "clausjonathan.fritzemeier@uni-duesseldorf.de"),
diff --git a/R/addReact.R b/R/addReact.R
index 1705cbaa550f462f8a34d63aca2d36868384d0f7..b7fe5c22c87a277b5afbd3c6aa9841e5382654b2 100644
--- a/R/addReact.R
+++ b/R/addReact.R
@@ -317,7 +317,7 @@ addReact <- function(model,
         if (is(model, "modelorg_irrev")) {
             mod_out <- modelorg_irrev(mod_id(model), mod_name(model))
             irrev(mod_out)     <- TRUE
-            matchrev(mod_out)  <- append(matchrev(model), 0)
+            matchrev(mod_out)  <- append(matchrev(model), 0L)
             
             revReactId <- max(irrev2rev(model))+1
             irrev2rev(mod_out) <- append(irrev2rev(model), revReactId)
diff --git a/inst/NEWS.Rd b/inst/NEWS.Rd
index 82b09df06cae065a8d2b1d1c2a024eee7625ca5f..2875c437eeb4e21e56ff3852c94e77b73c3e79ca 100644
--- a/inst/NEWS.Rd
+++ b/inst/NEWS.Rd
@@ -6,6 +6,12 @@
 
 \newcommand{\CRANpkg}{\href{http://CRAN.R-project.org/package=#1}{\pkg{#1}}}
 
+\section{Changes in version 1.3.3 2015-11-25}{
+  \itemize{
+    \item \code{addReact} crashed for irreversible models.
+  }
+}
+% ---------------------------------------------------------------------------- %
 \section{Changes in version 1.3.2 2015-10-21}{
   \itemize{
   	\item New Algorithm \code{fbaEasyConstraint} and \code{mtfEasyConstraint} 
@@ -14,6 +20,7 @@
     \item \code{switch} needs the first parameter explicitly named.
   }
 }
+% ---------------------------------------------------------------------------- %
 
 \section{Changes in version 1.3.1 2015-10-02}{
   \itemize{
@@ -21,6 +28,7 @@
     \item \code{deadEndMetabolite()} could miss deadEndMetabolites if reactions differ in stoichiometry e.g. 1 and 2.
   }
 }
+% ---------------------------------------------------------------------------- %
 
 \section{Changes in version 1.3.1 2015-08-06}{
   \itemize{