Check original Play! Framework migration documentation first:
a) change Play! version from
<properties>
...
<play2.version>2.4.11</play2.version>
</properties>
to
<properties>
...
<play2.version>2.5.15</play2.version>
</properties>
b) if using Specs2 tests remove repository definition (all artifacts are in Maven central repository)
<repositories>
<repository>
<id>scalaz-bintray</id>
<name>Scalaz Bintray - releases</name>
<url>https://dl.bintray.com/scalaz/releases/</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
c) add dependency
<dependency>
<groupId>com.typesafe.play</groupId>
<artifactId>play-logback_2.11</artifactId>
<version>${play2.version}</version>
<scope>runtime</scope>
</dependency>
d) default router generator type has changed from static to injected, add or remove configuration parameter
<plugin>
<groupId>com.google.code.play2-maven-plugin</groupId>
<artifactId>play2-maven-plugin</artifactId>
<version>${play2.plugin.version}</version>
<extensions>true</extensions>
<configuration>
...
<routesGenerator>static</routesGenerator>
</configuration>
</plugin>
<plugin>
<groupId>com.google.code.play2-maven-plugin</groupId>
<artifactId>play2-maven-plugin</artifactId>
<version>${play2.plugin.version}</version>
<extensions>true</extensions>
<configuration>
...
<!-- remove <routesGenerator>injected</routesGenerator> -->
</configuration>
</plugin>