Recently we downloaded new version of ICEpdf pro(5.1.0). Now it has groupId = 'org.icepdf.pro' for all libraries (icepdf-core, icepdf-pro, icepdf-pro-intl, icepdf-viewer).

But icepdf-viewer dependence on icepdf-core with group id = 'org.icepdf'.

Look at .pom file:
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>org.icepdf.pro</groupId>
    <artifactId>icepdf-viewer</artifactId>
    <version>5.1.0</version>
    <packaging>jar</packaging>
    <name>ICEpdf Viewer RI</name>
    <url>http://www.icefaces.org&lt;/url>
    <description>ICEpdf PDF Viewer Reference Implementation (RI)</description>

    <dependencies>

        <dependency>
            <groupId>org.icepdf</groupId>
            <artifactId>icepdf-core</artifactId>
            <version>5.1.0</version>
        </dependency>
...
    </dependencies>
</project>