diff --git a/CHANGELOG b/CHANGELOG
index c0c8c1a..9967549 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,13 @@
 CHANGELOG
 =========
 
+2.2.0
+-----
+
+* Upgrade sevntu to 1.23.1
+* Upgrade checkstyle to 7.6
+* Detect sync conflicts
+
 2.1.3
 -----
 
diff --git a/README.md b/README.md
index 6b6028c..99a6525 100644
--- a/README.md
+++ b/README.md
@@ -219,6 +219,7 @@ Rule|Level|Source|Enabled|Suppressable
 [Regexp](#regexp)|unspecified|checkstyle||
 [RegexpHeader](#regexpheader)|unspecified|checkstyle||
 [RegexpMultiline](#regexpmultiline)|unspecified|checkstyle||
+[RegexpOnFilename](#regexponfilename)|layout|checkstyle|Yes|
 [RegexpOnFilename](#regexponfilename)|unspecified|checkstyle||
 [RegexpSingleline](#regexpsingleline)|unspecified|checkstyle||
 [RegexpSinglelineJava](#regexpsinglelinejava)|unspecified|checkstyle||
@@ -274,6 +275,22 @@ The following is a list of each of the checks and the expectations each has on y
 
 Rules are listed in alphabetical order.
 
+#### [RegexpOnFilename](http://checkstyle.sourceforge.net/config_regexp.html#RegexpOnFilename)
+
+Checks for the existence of forbidden java file names.
+
+File names are forbidden if they match the pattern `(.sync-conflict-| conflicted copy )`.
+
+N.B. only `*.java` files are checked.
+
+This check is intended to detect Syncthing and Dropbox conflict files.
+
+e.g.
+````
+DataClass (Bob's conflicted copy 2017-03-11).java
+DataClass.sync-conflict-20170311-1648.java
+````
+
 #### [AbbreviationAsWordInName](http://checkstyle.sourceforge.net/config_naming.html#AbbreviationAsWordInName)
 
 Enforces proper `CamelCase` and avoids sequences of consecutive uppercase characters in identifiers. Does not apply to @Overridden methods.
diff --git a/builder/pom.xml b/builder/pom.xml
index d76d9c6..0648ad5 100644
--- a/builder/pom.xml
+++ b/builder/pom.xml
@@ -12,7 +12,7 @@
     </parent>
 
     <artifactId>kemitix-checkstyle-ruleset-builder</artifactId>
-    <version>2.1.3</version>
+    <version>2.2.0</version>
     <packaging>jar</packaging>
 
     <name>Kemitix Checkstyle Ruleset Builder</name>
diff --git a/builder/src/main/resources/application.yml b/builder/src/main/resources/application.yml
index 674e39a..02ca4d6 100644
--- a/builder/src/main/resources/application.yml
+++ b/builder/src/main/resources/application.yml
@@ -12,6 +12,16 @@ template:
     readme-template: builder/src/main/resources/README-template.md
     readme-fragments: builder/src/main/resources/rules
 rules:
+    -
+        name: RegexpOnFilename
+        parent: CHECKER
+        level: LAYOUT
+        enabled: true
+        source: CHECKSTYLE
+        uri: http://checkstyle.sourceforge.net/config_regexp.html#RegexpOnFilename
+        properties:
+            fileNamePattern: "(.sync-conflict-| conflicted copy )"
+            match: true
     -
         name: AbbreviationAsWordInName
         parent: TREEWALKER
diff --git a/builder/src/main/resources/rules/RegexpOnFilename.md b/builder/src/main/resources/rules/RegexpOnFilename.md
new file mode 100644
index 0000000..5319e2c
--- /dev/null
+++ b/builder/src/main/resources/rules/RegexpOnFilename.md
@@ -0,0 +1,15 @@
+
+Checks for the existence of forbidden java file names.
+
+File names are forbidden if they match the pattern `(.sync-conflict-| conflicted copy )`.
+
+N.B. only `*.java` files are checked.
+
+This check is intended to detect Syncthing and Dropbox conflict files.
+
+e.g.
+````
+DataClass (Bob's conflicted copy 2017-03-11).java
+DataClass.sync-conflict-20170311-1648.java
+````
+
diff --git a/plugin-sample/pom.xml b/plugin-sample/pom.xml
index fe764fb..58af8ba 100644
--- a/plugin-sample/pom.xml
+++ b/plugin-sample/pom.xml
@@ -8,7 +8,7 @@
     <!-- don't use parent to avoid using grandparent's checkstyle configuration -->
     <groupId>net.kemitix</groupId>
     <artifactId>kemitix-checkstyle-ruleset-plugin-sample</artifactId>
-    <version>2.1.3</version>
+    <version>2.2.0</version>
 
     <name>Kemitix Checkstyle Ruleset Plugin Sample</name>
     <description>Sample usage of the Kemitix Checkstyle Ruleset Plugin</description>
diff --git a/plugin/pom.xml b/plugin/pom.xml
index a227ab3..4bd6181 100644
--- a/plugin/pom.xml
+++ b/plugin/pom.xml
@@ -7,7 +7,7 @@
     <parent>
         <groupId>net.kemitix</groupId>
         <artifactId>kemitix-checkstyle-ruleset-parent</artifactId>
-        <version>2.1.3</version>
+        <version>2.2.0</version>
     </parent>
 
     <artifactId>kemitix-checkstyle-ruleset-maven-plugin</artifactId>
diff --git a/pom.xml b/pom.xml
index 1d75051..dc2b228 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
 
     <groupId>net.kemitix</groupId>
     <artifactId>kemitix-checkstyle-ruleset-parent</artifactId>
-    <version>2.1.3</version>
+    <version>2.2.0</version>
     <packaging>pom</packaging>
 
     <name>Kemitix Checkstyle Ruleset (Parent)</name>
@@ -21,8 +21,8 @@
         <maven-deploy-plugin.version>2.8.2</maven-deploy-plugin.version>
 
         <maven-checkstyle-plugin.version>2.17</maven-checkstyle-plugin.version>
-        <checkstyle.version>7.5.1</checkstyle.version>
-        <sevntu.version>1.23.0</sevntu.version>
+        <checkstyle.version>7.6</checkstyle.version>
+        <sevntu.version>1.23.1</sevntu.version>
     </properties>
 
     <modules>
diff --git a/ruleset/pom.xml b/ruleset/pom.xml
index 1a9d912..c8058c1 100644
--- a/ruleset/pom.xml
+++ b/ruleset/pom.xml
@@ -7,11 +7,11 @@
     <parent>
         <groupId>net.kemitix</groupId>
         <artifactId>kemitix-checkstyle-ruleset-parent</artifactId>
-        <version>2.1.3</version>
+        <version>2.2.0</version>
     </parent>
 
     <artifactId>kemitix-checkstyle-ruleset</artifactId>
-    <version>2.1.3</version>
+    <version>2.2.0</version>
     <packaging>jar</packaging>
 
     <name>Kemitix Checkstyle Ruleset</name>
diff --git a/ruleset/src/main/resources/net/kemitix/checkstyle-1-layout.xml b/ruleset/src/main/resources/net/kemitix/checkstyle-1-layout.xml
index 72c0d46..c7c3f72 100644
--- a/ruleset/src/main/resources/net/kemitix/checkstyle-1-layout.xml
+++ b/ruleset/src/main/resources/net/kemitix/checkstyle-1-layout.xml
@@ -4,7 +4,11 @@
         "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
 <module name="Checker">
 
-    <module name="FileTabCharacter"/>
+    <module name="RegexpOnFilename">
+    <property name="fileNamePattern" value="(.sync-conflict-| conflicted copy )"/>
+<property name="match" value="true"/>
+</module>
+<module name="FileTabCharacter"/>
 <module name="Header">
     <property name="fileExtensions" value="java"/>
 <property name="headerFile" value="LICENSE.txt"/>
diff --git a/ruleset/src/main/resources/net/kemitix/checkstyle-2-naming.xml b/ruleset/src/main/resources/net/kemitix/checkstyle-2-naming.xml
index d27be47..040fe94 100644
--- a/ruleset/src/main/resources/net/kemitix/checkstyle-2-naming.xml
+++ b/ruleset/src/main/resources/net/kemitix/checkstyle-2-naming.xml
@@ -4,7 +4,11 @@
         "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
 <module name="Checker">
 
-    <module name="FileTabCharacter"/>
+    <module name="RegexpOnFilename">
+    <property name="fileNamePattern" value="(.sync-conflict-| conflicted copy )"/>
+<property name="match" value="true"/>
+</module>
+<module name="FileTabCharacter"/>
 <module name="Header">
     <property name="fileExtensions" value="java"/>
 <property name="headerFile" value="LICENSE.txt"/>
diff --git a/ruleset/src/main/resources/net/kemitix/checkstyle-3-javadoc.xml b/ruleset/src/main/resources/net/kemitix/checkstyle-3-javadoc.xml
index 1fe56af..811e021 100644
--- a/ruleset/src/main/resources/net/kemitix/checkstyle-3-javadoc.xml
+++ b/ruleset/src/main/resources/net/kemitix/checkstyle-3-javadoc.xml
@@ -4,7 +4,11 @@
         "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
 <module name="Checker">
 
-    <module name="FileTabCharacter"/>
+    <module name="RegexpOnFilename">
+    <property name="fileNamePattern" value="(.sync-conflict-| conflicted copy )"/>
+<property name="match" value="true"/>
+</module>
+<module name="FileTabCharacter"/>
 <module name="Header">
     <property name="fileExtensions" value="java"/>
 <property name="headerFile" value="LICENSE.txt"/>
diff --git a/ruleset/src/main/resources/net/kemitix/checkstyle-4-tweaks.xml b/ruleset/src/main/resources/net/kemitix/checkstyle-4-tweaks.xml
index cf4ce72..50b1a88 100644
--- a/ruleset/src/main/resources/net/kemitix/checkstyle-4-tweaks.xml
+++ b/ruleset/src/main/resources/net/kemitix/checkstyle-4-tweaks.xml
@@ -4,7 +4,11 @@
         "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
 <module name="Checker">
 
-    <module name="FileTabCharacter"/>
+    <module name="RegexpOnFilename">
+    <property name="fileNamePattern" value="(.sync-conflict-| conflicted copy )"/>
+<property name="match" value="true"/>
+</module>
+<module name="FileTabCharacter"/>
 <module name="Header">
     <property name="fileExtensions" value="java"/>
 <property name="headerFile" value="LICENSE.txt"/>
diff --git a/ruleset/src/main/resources/net/kemitix/checkstyle-5-complexity.xml b/ruleset/src/main/resources/net/kemitix/checkstyle-5-complexity.xml
index 44de9aa..b258137 100644
--- a/ruleset/src/main/resources/net/kemitix/checkstyle-5-complexity.xml
+++ b/ruleset/src/main/resources/net/kemitix/checkstyle-5-complexity.xml
@@ -4,7 +4,11 @@
         "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
 <module name="Checker">
 
-    <module name="FileLength"/>
+    <module name="RegexpOnFilename">
+    <property name="fileNamePattern" value="(.sync-conflict-| conflicted copy )"/>
+<property name="match" value="true"/>
+</module>
+<module name="FileLength"/>
 <module name="FileTabCharacter"/>
 <module name="Header">
     <property name="fileExtensions" value="java"/>