diff --git a/lectures/lectureslides.cls b/lectures/lectureslides.cls
index 61cb8dd..cf39f0e 100644
--- a/lectures/lectureslides.cls
+++ b/lectures/lectureslides.cls
@@ -1,4 +1,4 @@
-\def\filedate{1 February 2014}
+\def\filedate{2 August 2018}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %
 % Document class for lecture slides.
@@ -15,12 +15,13 @@
 % v1.2   Added TikZ package and grid macro, and deprecated PGF.
 % v1.3   Added support for configurable class types.
 % v1.3.1 Fixed regression that eliminated paper title from title page.
+% v1.3.2 Added text highlighting and \alertbf macros.
 %
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \NeedsTeXFormat{LaTeX2e}[2001/06/01]
 \ProvidesClass{lectureslides}%
-         [2014/07/06 INFO lecture slides style, v.1.3.1]
+         [2018/08/02 INFO lecture slides style, v.1.3.2]
 
 % "Stream of conciousness" chapters vs. explicit individual classes. NOTE:
 % you can't have both chapters and classes! This is because we use the same
@@ -98,8 +99,9 @@
 }
 
 
-% Bold-face text using the structure colour.
+% Bold-face text using the structure or alert colour.
 \newcommand<>{\structurebf}[1]{\structure#2{\textbf{#1}}}
+\newcommand<>{\alertbf}[1]{\alert#2{\textbf{#1}}}
 
 
 % Define the standard beamer colours as actual colours, as we use them
@@ -112,6 +114,17 @@
 \newcommand<>{\strikeout}[1]{\alt#2{\sout{#1}}{#1}}
 
 
+% Coloured highlighting of text (via Mark George).
+% \vphantom gives correct ascender and descender height for box.
+\newcommand{\highlight}[2][yellow!75]{\setlength{\fboxsep}{1pt}\hskip-1pt\colorbox{#1}{\vphantom{dy}#2}}
+
+% Uses the same spacing as \highlight, but does no highlighting.  Use on the
+% original code when using incremental highlighting.
+\newcommand{\nohighlight}[1]{\highlight[white!0]{#1}}
+
+\newcommand{\error}[1]{\highlight[red!75]{#1}}
+
+
 % Document setup.
 \author{}
 \if@chapters