diff --git a/README.md b/README.md
index bd15a31..524160b 100644
--- a/README.md
+++ b/README.md
@@ -13,7 +13,7 @@ MedicMobileImpact
 
 https://www.rstudio.com/
 
- Step 3.  Open RStudio, and install the knitr package.  Do this by clicking _Packages_ tab, then click the _Install Packages_ button.  Search for "knitr", make sure _Install dependencies_ is checked, and click _Install_.
+ Step 3.  Open RStudio, and install the knitr package.  Do this by clicking _Packages_ tab, then click the _Install Packages_ button.  Search for "knitr", make sure _Install dependencies_ is checked, and click _Install_.  This procedure has been tested using knitr 1.5.  To make sure you have the latest knitr update, in RStudio in the _Packages_ tab click _Check for Updates_ and follow the instructions.
 
  Step 4.  Enable knitr in RStudio.  Do this by clicking _Preferences_, then clicking the _Sweave_ tab.  Next to "Weave Rnw files using", select knitr from the drop-down menu.  Click _Apply_ and _Ok_.