diff --git a/1.3.x/multi/multi__managing_spans_with_annotations.html b/1.3.x/multi/multi__managing_spans_with_annotations.html
index 4820f37f8..7f7996ef4 100644
--- a/1.3.x/multi/multi__managing_spans_with_annotations.html
+++ b/1.3.x/multi/multi__managing_spans_with_annotations.html
@@ -32,14 +32,16 @@ with the <code class="literal">@NewSpan</code> annotation you can also add logs
 <span xmlns:d="http://docbook.org/ns/docbook" class="hl-comment">// method execution</span>
 <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">this</span>.testBean.testMethod11(<span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"test"</span>);</pre><p>That way the span will get continued and:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">logs with name <code class="literal">testMethod11.before</code> and <code class="literal">testMethod11.after</code> will be created</li><li class="listitem">if an exception will be thrown a log <code class="literal">testMethod11.afterFailure</code> will also be created</li><li class="listitem">tag with key <code class="literal">testTag11</code> and value <code class="literal">test</code> will be created</li></ul></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_more_advanced_tag_setting" href="#_more_advanced_tag_setting"></a>8.4&nbsp;More advanced tag setting</h2></div></div></div><p>There are 3 different ways to add tags to a span. All of them are controlled by the <code class="literal">SpanTag</code> annotation.
 Precedence is:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">try with the bean of <code class="literal">TagValueResolver</code> type and provided name</li><li class="listitem">if one hasn&#8217;t provided the bean name, try to evaluate an expression. We&#8217;re searching for a <code class="literal">TagValueExpressionResolver</code> bean.
-The default implementation uses SPEL expression resolution.</li><li class="listitem">if one hasn&#8217;t provided any expression to evaluate just return a <code class="literal">toString()</code> value of the parameter</li></ul></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_custom_extractor" href="#_custom_extractor"></a>8.4.1&nbsp;Custom extractor</h3></div></div></div><p>The value of the tag for following method will be computed by an implementation of <code class="literal">TagValueResolver</code> interface.
+The default implementation uses SPEL expression resolution. If we do not find any expression to evaluate, return the <code class="literal">toString()</code>
+value of the parameter.
+<span class="strong"><strong>IMPORTANT</strong></span> You can only reference properties from the SPEL expression. Method execution is not allowed due to security constraints.</li><li class="listitem">if one hasn&#8217;t provided any expression to evaluate just return a <code class="literal">toString()</code> value of the parameter</li></ul></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_custom_extractor" href="#_custom_extractor"></a>8.4.1&nbsp;Custom extractor</h3></div></div></div><p>The value of the tag for following method will be computed by an implementation of <code class="literal">TagValueResolver</code> interface.
 Its class name has to be passed as the value of the <code class="literal">resolver</code> attribute.</p><p>Having such an annotated method:</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@NewSpan</span></em>
 <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">void</span> getAnnotationForTagValueResolver(<em><span class="hl-annotation" style="color: gray">@SpanTag(key = "test", resolver = TagValueResolver.class)</span></em> String test) {
 }</pre><p>and such a <code class="literal">TagValueResolver</code> bean implementation</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@Bean(name = "myCustomTagValueResolver")</span></em>
 <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> TagValueResolver tagValueResolver() {
 	<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">return</span> parameter -&gt; <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"Value from myCustomTagValueResolver"</span>;
 }</pre><p>Will lead to setting of a tag value equal to <code class="literal">Value from myCustomTagValueResolver</code>.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_resolving_expressions_for_value" href="#_resolving_expressions_for_value"></a>8.4.2&nbsp;Resolving expressions for value</h3></div></div></div><p>Having such an annotated method:</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@NewSpan</span></em>
-<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">void</span> getAnnotationForTagValueExpression(<em><span class="hl-annotation" style="color: gray">@SpanTag(key = "test", expression = "length() + ' characters'")</span></em> String test) {
+<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">void</span> getAnnotationForTagValueExpression(<em><span class="hl-annotation" style="color: gray">@SpanTag(key = "test", expression = "'hello' + ' characters'")</span></em> String test) {
 }</pre><p>and no custom implementation of a <code class="literal">TagValueExpressionResolver</code> will lead to evaluation of the SPEL expression and a tag with value <code class="literal">4 characters</code> will be set on the span.
 If you want to use some other expression resolution mechanism you can create your own implementation
 of the bean.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_using_tostring_method" href="#_using_tostring_method"></a>8.4.3&nbsp;Using toString method</h3></div></div></div><p>Having such an annotated method:</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@NewSpan</span></em>
diff --git a/1.3.x/single/spring-cloud-sleuth.html b/1.3.x/single/spring-cloud-sleuth.html
index 7924c4d33..4555fa7f3 100644
--- a/1.3.x/single/spring-cloud-sleuth.html
+++ b/1.3.x/single/spring-cloud-sleuth.html
@@ -405,14 +405,16 @@ with the <code class="literal">@NewSpan</code> annotation you can also add logs
 <span xmlns:d="http://docbook.org/ns/docbook" class="hl-comment">// method execution</span>
 <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">this</span>.testBean.testMethod11(<span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"test"</span>);</pre><p>That way the span will get continued and:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">logs with name <code class="literal">testMethod11.before</code> and <code class="literal">testMethod11.after</code> will be created</li><li class="listitem">if an exception will be thrown a log <code class="literal">testMethod11.afterFailure</code> will also be created</li><li class="listitem">tag with key <code class="literal">testTag11</code> and value <code class="literal">test</code> will be created</li></ul></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_more_advanced_tag_setting" href="#_more_advanced_tag_setting"></a>8.4&nbsp;More advanced tag setting</h2></div></div></div><p>There are 3 different ways to add tags to a span. All of them are controlled by the <code class="literal">SpanTag</code> annotation.
 Precedence is:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">try with the bean of <code class="literal">TagValueResolver</code> type and provided name</li><li class="listitem">if one hasn&#8217;t provided the bean name, try to evaluate an expression. We&#8217;re searching for a <code class="literal">TagValueExpressionResolver</code> bean.
-The default implementation uses SPEL expression resolution.</li><li class="listitem">if one hasn&#8217;t provided any expression to evaluate just return a <code class="literal">toString()</code> value of the parameter</li></ul></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_custom_extractor" href="#_custom_extractor"></a>8.4.1&nbsp;Custom extractor</h3></div></div></div><p>The value of the tag for following method will be computed by an implementation of <code class="literal">TagValueResolver</code> interface.
+The default implementation uses SPEL expression resolution. If we do not find any expression to evaluate, return the <code class="literal">toString()</code>
+value of the parameter.
+<span class="strong"><strong>IMPORTANT</strong></span> You can only reference properties from the SPEL expression. Method execution is not allowed due to security constraints.</li><li class="listitem">if one hasn&#8217;t provided any expression to evaluate just return a <code class="literal">toString()</code> value of the parameter</li></ul></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_custom_extractor" href="#_custom_extractor"></a>8.4.1&nbsp;Custom extractor</h3></div></div></div><p>The value of the tag for following method will be computed by an implementation of <code class="literal">TagValueResolver</code> interface.
 Its class name has to be passed as the value of the <code class="literal">resolver</code> attribute.</p><p>Having such an annotated method:</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@NewSpan</span></em>
 <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">void</span> getAnnotationForTagValueResolver(<em><span class="hl-annotation" style="color: gray">@SpanTag(key = "test", resolver = TagValueResolver.class)</span></em> String test) {
 }</pre><p>and such a <code class="literal">TagValueResolver</code> bean implementation</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@Bean(name = "myCustomTagValueResolver")</span></em>
 <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> TagValueResolver tagValueResolver() {
 	<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">return</span> parameter -&gt; <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"Value from myCustomTagValueResolver"</span>;
 }</pre><p>Will lead to setting of a tag value equal to <code class="literal">Value from myCustomTagValueResolver</code>.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_resolving_expressions_for_value" href="#_resolving_expressions_for_value"></a>8.4.2&nbsp;Resolving expressions for value</h3></div></div></div><p>Having such an annotated method:</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@NewSpan</span></em>
-<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">void</span> getAnnotationForTagValueExpression(<em><span class="hl-annotation" style="color: gray">@SpanTag(key = "test", expression = "length() + ' characters'")</span></em> String test) {
+<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">void</span> getAnnotationForTagValueExpression(<em><span class="hl-annotation" style="color: gray">@SpanTag(key = "test", expression = "'hello' + ' characters'")</span></em> String test) {
 }</pre><p>and no custom implementation of a <code class="literal">TagValueExpressionResolver</code> will lead to evaluation of the SPEL expression and a tag with value <code class="literal">4 characters</code> will be set on the span.
 If you want to use some other expression resolution mechanism you can create your own implementation
 of the bean.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_using_tostring_method" href="#_using_tostring_method"></a>8.4.3&nbsp;Using toString method</h3></div></div></div><p>Having such an annotated method:</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@NewSpan</span></em>
diff --git a/1.3.x/spring-cloud-sleuth.xml b/1.3.x/spring-cloud-sleuth.xml
index 045b98fc0..d022f28aa 100644
--- a/1.3.x/spring-cloud-sleuth.xml
+++ b/1.3.x/spring-cloud-sleuth.xml
@@ -4,7 +4,7 @@
 <book xmlns="http://docbook.org/ns/docbook" xmlns:xl="http://www.w3.org/1999/xlink" version="5.0" xml:lang="en">
 <info>
 <title>Spring Cloud Sleuth</title>
-<date>2018-04-06</date>
+<date>2018-04-07</date>
 <author>
 <personname>
 <firstname>Adrian Cole, Spencer Gibb, Marcin Grzejszczak, Dave Syer</firstname>
@@ -1004,7 +1004,9 @@ Precedence is:</simpara>
 </listitem>
 <listitem>
 <simpara>if one hasn&#8217;t provided the bean name, try to evaluate an expression. We&#8217;re searching for a <literal>TagValueExpressionResolver</literal> bean.
-The default implementation uses SPEL expression resolution.</simpara>
+The default implementation uses SPEL expression resolution. If we do not find any expression to evaluate, return the <literal>toString()</literal>
+value of the parameter.
+<emphasis role="strong">IMPORTANT</emphasis> You can only reference properties from the SPEL expression. Method execution is not allowed due to security constraints.</simpara>
 </listitem>
 <listitem>
 <simpara>if one hasn&#8217;t provided any expression to evaluate just return a <literal>toString()</literal> value of the parameter</simpara>
@@ -1029,7 +1031,7 @@ public TagValueResolver tagValueResolver() {
 <title>Resolving expressions for value</title>
 <simpara>Having such an annotated method:</simpara>
 <programlisting language="java" linenumbering="unnumbered">@NewSpan
-public void getAnnotationForTagValueExpression(@SpanTag(key = "test", expression = "length() + ' characters'") String test) {
+public void getAnnotationForTagValueExpression(@SpanTag(key = "test", expression = "'hello' + ' characters'") String test) {
 }</programlisting>
 <simpara>and no custom implementation of a <literal>TagValueExpressionResolver</literal> will lead to evaluation of the SPEL expression and a tag with value <literal>4 characters</literal> will be set on the span.
 If you want to use some other expression resolution mechanism you can create your own implementation