Dependency convergence error

Question

After updating Firefox I changed versions of libraries to higher ones. Following errors appeard: [ERROR] Dependency convergence error for commons-collections:commons-collections:3.2.2 paths to dependency are:

[ERROR] +-net:serenity.pom.gradle:0.0.1-SNAPSHOT
[ERROR] +-net.serenity-bdd:serenity-core:1.1.29-rc.3
[ERROR] +-org.seleniumhq.selenium:htmlunit-driver:2.20
[ERROR] +-commons-collections:commons-collections:3.2.2
[ERROR] and
[ERROR] +-net:serenity.pom.gradle:0.0.1-SNAPSHOT
[ERROR] +-net.serenity-bdd:serenity-core:1.1.29-rc.3
[ERROR] +-io.appium:java-client:3.3.0
[ERROR] +-commons-validator:commons-validator:1.4.1
[ERROR] +-commons-collections:commons-collections:3.2.1
[ERROR] and
[ERROR] +-net:serenity.pom.gradle:0.0.1-SNAPSHOT
[ERROR] +-net.serenity-bdd:serenity-core:1.1.29-rc.3
[ERROR] +-commons-collections:commons-collections:3.2.2
[ERROR] ]
[ERROR] -> [Help 1]

Dependency tree looks like:

[INFO] +- net.serenity-bdd:serenity-core:jar:1.1.29-rc.3:test
[INFO] |  +- org.seleniumhq.selenium:htmlunit-driver:jar:2.20:test
[INFO] |  +- commons-collections:commons-collections:jar:3.2.2:test
[INFO] |  +- io.appium:java-client:jar:3.3.0:test
[INFO] |  |  \- commons-validator:commons-validator:jar:1.4.1:test
[INFO] |  |     +- commons-beanutils:commons-beanutils:jar:1.8.3:test
[INFO] |  |     \- commons-digester:commons-digester:jar:1.8.1:test

How to solve this problem? Can I manually switch the library?

PS Here is my pom.xml

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>net.serenity-bdd</groupId>
        <artifactId>serenity-core</artifactId>
        <version>1.1.29-rc.3</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-simple</artifactId>
        <version>1.7.7</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>net.serenity-bdd</groupId>
        <artifactId>serenity-jbehave</artifactId>
        <version>1.9.0</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.assertj</groupId>
        <artifactId>assertj-core</artifactId>
        <version>3.2.0</version>
        <scope>test</scope>
    </dependency>
</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-enforcer-plugin</artifactId>
            <version>1.4</version>
            <executions>
                <execution>
                    <id>verify</id>
                    <phase>validate</phase>
                    <goals>
                        <goal>enforce</goal>
                    </goals>
                    <inherited>true</inherited>
                </execution>
            </executions>
            <configuration>
                <failFast>true</failFast>
                <rules>
                    <DependencyConvergence></DependencyConvergence>
                    <requireReleaseDeps>
                        <onlyWhenRelease>true</onlyWhenRelease>
                    </requireReleaseDeps>
                    <requireJavaVersion>
                        <version>${java.version}</version>
                    </requireJavaVersion>
                </rules>
            </configuration>
        </plugin>
        <plugin>
            <artifactId>maven-failsafe-plugin</artifactId>
            <version>2.18</version>
            <configuration>
                <includes>
                    <include>src/test/java/*.java </include>
                </includes>
            </configuration>
            <executions>
                <execution>
                    <goals>
                        <goal>integration-test</goal>
                        <goal>verify</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.2</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
            </configuration>
        </plugin>
        <plugin>
            <groupId>net.serenity-bdd.maven.plugins</groupId>
            <artifactId>serenity-maven-plugin</artifactId>
            <version>1.1.29-rc.1</version>
            <dependencies>
                <dependency>
                    <groupId>net.serenity-bdd</groupId>
                    <artifactId>serenity-core</artifactId>
                    <version>1.1.29-rc.3</version>
                </dependency>
            </dependencies>
            <executions>
                <execution>
                    <id>serenity-reports</id>
                    <phase>post-integration-test</phase>
                    <goals>
                        <goal>aggregate</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

Answer 1

See POM Reference, Exclusions:

Exclusions explicitly tell Maven that you don't want to include the specified project that is a dependency of this dependency (in other words, its transitive dependency).

See also Apache Maven Enforcer Rules, Dependency Convergence:

If a project has two dependencies, A and B, both depending on the same artifact, C, this rule will fail the build if A depends on a different version of C then the version of C depended on by B.

[...]

And this will succeed.

   <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-jdk14</artifactId>
      <version>1.6.1</version>
    </dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-nop</artifactId>
      <version>1.6.0</version>
      <exclusions>
        <exclusion>
          <groupId>org.slf4j</groupId>
          <artifactId>slf4j-api</artifactId>
        </exclusion>
      </exclusions>
    </dependency>