Github build is missing a 'Version' class

[richardm@roma terrier-core-5.x]$mvn package
[INFO] Scanning for projects...
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Build Order:
[INFO]
[INFO] Terrier Information Retrieval Platform
[INFO] terrier-retrieval-api
[INFO] terrier-rest-client
[INFO] terrier-core
[INFO] terrier-batch-indexers
[INFO] terrier-batch-retrieval
[INFO] terrier-learning
[INFO] terrier-logging
[INFO] terrier-realtime
[INFO] terrier-rest-server
[INFO] terrier-tests
[INFO] terrier-concurrent
[INFO] terrier-integer-compression
[INFO] terrier-website-search
[INFO] terrier-assemblies
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building Terrier Information Retrieval Platform 5.0
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-enforcer-plugin:1.4.1:enforce (enforce-maven) @ terrier-platform ---
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building terrier-retrieval-api 5.0
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-enforcer-plugin:1.4.1:enforce (enforce-maven) @ terrier-retrieval-api ---
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ terrier-retrieval-api ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /local/tr.kba/GitHub/terrier-core-5.x/modules/retrieval-api/src/main/resources
[INFO]
[INFO] --- maven-compiler-plugin:3.7.0:compile (default-compile) @ terrier-retrieval-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ terrier-retrieval-api ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /local/tr.kba/GitHub/terrier-core-5.x/modules/retrieval-api/src/test/resources
[INFO]
[INFO] --- maven-compiler-plugin:3.7.0:testCompile (default-testCompile) @ terrier-retrieval-api ---
[INFO] No sources to compile
[INFO]
[INFO] --- maven-surefire-plugin:2.10:test (default-test) @ terrier-retrieval-api ---
[INFO] No tests to run.
[INFO] Surefire report directory: /local/tr.kba/GitHub/terrier-core-5.x/modules/retrieval-api/target/surefire-reports

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 T E S T S
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Results :

Tests run: 0, Failures: 0, Errors: 0, Skipped: 0

[INFO]
[INFO] --- maven-jar-plugin:2.3.2:jar (default-jar) @ terrier-retrieval-api ---
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building terrier-rest-client 5.0
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-enforcer-plugin:1.4.1:enforce (enforce-maven) @ terrier-rest-client ---
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ terrier-rest-client ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 1 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.7.0:compile (default-compile) @ terrier-rest-client ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ terrier-rest-client ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /local/tr.kba/GitHub/terrier-core-5.x/modules/rest-client/src/test/resources
[INFO]
[INFO] --- maven-compiler-plugin:3.7.0:testCompile (default-testCompile) @ terrier-rest-client ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.10:test (default-test) @ terrier-rest-client ---
[INFO] Surefire report directory: /local/tr.kba/GitHub/terrier-core-5.x/modules/rest-client/target/surefire-reports

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 T E S T S
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Running org.terrier.rest.TestRest
Tests run: 0, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.002 sec

Results :

Tests run: 0, Failures: 0, Errors: 0, Skipped: 0

[INFO]
[INFO] --- maven-jar-plugin:2.3.2:jar (default-jar) @ terrier-rest-client ---
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building terrier-core 5.0
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-enforcer-plugin:1.4.1:enforce (enforce-maven) @ terrier-core ---
[INFO]
[INFO] --- javacc-maven-plugin:2.6:javacc (terrierql) @ terrier-core ---
[INFO] Skipping - all parsers are up to date
[INFO]
[INFO] --- javacc-maven-plugin:2.6:javacc (matchopql) @ terrier-core ---
[INFO] Skipping - all parsers are up to date
[INFO]
[INFO] --- build-helper-maven-plugin:1.8:add-source (default) @ terrier-core ---
[INFO] Source directory: /local/tr.kba/GitHub/terrier-core-5.x/modules/core/target/generated-sources/javacc added.
[INFO] Source directory: /local/tr.kba/GitHub/terrier-core-5.x/modules/core/target/generated-sources/version added.
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ terrier-core ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 4 resources
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (version-generation) @ terrier-core ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 4 resources
[INFO]
[INFO] --- maven-compiler-plugin:3.7.0:compile (default-compile) @ terrier-core ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 397 source files to /local/tr.kba/GitHub/terrier-core-5.x/modules/core/target/classes
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] /local/tr.kba/GitHub/terrier-core-5.x/modules/core/src/main/java/org/terrier/structures/IndexOnDisk.java:[40,18] error: cannot find symbol
  symbol: class Version
  location: package org.terrier
[ERROR] /local/tr.kba/GitHub/terrier-core-5.x/modules/core/src/main/java/org/terrier/applications/CLITool.java:[49,18] error: cannot find symbol
  symbol: class Version
  location: package org.terrier
[ERROR] /local/tr.kba/GitHub/terrier-core-5.x/modules/core/src/main/java/org/terrier/applications/CLITool.java:[172,43] error: cannot find symbol
  symbol: variable Version
  location: class HelpCLITool
[ERROR] /local/tr.kba/GitHub/terrier-core-5.x/modules/core/src/main/java/org/terrier/applications/CLITool.java:[127,43] error: cannot find symbol
  symbol: class Version
  location: package org.terrier
[ERROR] /local/tr.kba/GitHub/terrier-core-5.x/modules/core/src/main/java/org/terrier/structures/IndexOnDisk.java:[473,27] error: cannot find symbol
  symbol: variable Version
  location: class IndexOnDisk
[ERROR] /local/tr.kba/GitHub/terrier-core-5.x/modules/core/src/main/java/org/terrier/structures/IndexOnDisk.java:[475,119] error: cannot find symbol
  symbol: variable Version
  location: class IndexOnDisk
[INFO] 6 errors
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] Terrier Information Retrieval Platform ............ SUCCESS [1.267s]
[INFO] terrier-retrieval-api ............................. SUCCESS [2.184s]
[INFO] terrier-rest-client ............................... SUCCESS [0.436s]
[INFO] terrier-core ...................................... FAILURE [9.565s]
[INFO] terrier-batch-indexers ............................ SKIPPED
[INFO] terrier-batch-retrieval ........................... SKIPPED
[INFO] terrier-learning .................................. SKIPPED
[INFO] terrier-logging ................................... SKIPPED
[INFO] terrier-realtime .................................. SKIPPED
[INFO] terrier-rest-server ............................... SKIPPED
[INFO] terrier-tests ..................................... SKIPPED
[INFO] terrier-concurrent ................................ SKIPPED
[INFO] terrier-integer-compression ....................... SKIPPED
[INFO] terrier-website-search ............................ SKIPPED
[INFO] terrier-assemblies ................................ SKIPPED
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 13.741s
[INFO] Finished at: Thu Dec 20 11:02:30 GMT 2018
[INFO] Final Memory: 17M/481M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.7.0:compile (default-compile) on project terrier-core: Compilation failure: Compilation failure:
[ERROR] /local/tr.kba/GitHub/terrier-core-5.x/modules/core/src/main/java/org/terrier/structures/IndexOnDisk.java:[40,18] error: cannot find symbol
[ERROR] symbol: class Version
[ERROR] location: package org.terrier
[ERROR] /local/tr.kba/GitHub/terrier-core-5.x/modules/core/src/main/java/org/terrier/applications/CLITool.java:[49,18] error: cannot find symbol
[ERROR] symbol: class Version
[ERROR] location: package org.terrier
[ERROR] /local/tr.kba/GitHub/terrier-core-5.x/modules/core/src/main/java/org/terrier/applications/CLITool.java:[172,43] error: cannot find symbol
[ERROR] symbol: variable Version
[ERROR] location: class HelpCLITool
[ERROR] /local/tr.kba/GitHub/terrier-core-5.x/modules/core/src/main/java/org/terrier/applications/CLITool.java:[127,43] error: cannot find symbol
[ERROR] symbol: class Version
[ERROR] location: package org.terrier
[ERROR] /local/tr.kba/GitHub/terrier-core-5.x/modules/core/src/main/java/org/terrier/structures/IndexOnDisk.java:[473,27] error: cannot find symbol
[ERROR] symbol: variable Version
[ERROR] location: class IndexOnDisk
[ERROR] /local/tr.kba/GitHub/terrier-core-5.x/modules/core/src/main/java/org/terrier/structures/IndexOnDisk.java:[475,119] error: cannot find symbol
[ERROR] symbol: variable Version
[ERROR] location: class IndexOnDisk
[ERROR] -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException
[ERROR]
[ERROR] After correcting the problems, you can resume the build with the command
[ERROR] mvn <goals> -rf :terrier-core