Build error v1.8.1

I need some help building openhab. I have chosen to checkout v1.8.1 (for no special reason, just thought it was a stable version). Building runs into an error. I am not an expert, but my guess is, that the module uses an old version of apache-common-lang or something like that.

How do I solve this problem?

So I did:
…>mvn checkout v1.8.1

Checking out files: 100% (4259/4259), done.
A bundles/binding/org.openhab.binding.homematic/.settings/org.eclipse.jdt.core.prefs
Previous HEAD position was e83d021… prepare for 1.8.3 release
HEAD is now at 0693e6d… cherry-picked #3950
imac2-vandenzen-nl:openhab carl$ git status
HEAD detached at v1.8.1
Changes to be committed:
(use “git reset HEAD …” to unstage)

new file: bundles/binding/org.openhab.binding.homematic/.settings/org.eclipse.jdt.core.prefs

imac2-vandenzen-nl:openhab carl$ mvn -o clean install

[INFO] Scanning for projects…
[INFO] Computing target platform for MavenProject: org.openhab.action:org.openhab.action.mail:1.8.1-SNAPSHOT @ /Users/carl/ontwikkelingen/openhab/install/openhab2-master/git/openhab/bundles/action/org.openhab.action.mail/pom.xml
[INFO] openHAB Target Platform … SKIPPED
[INFO] openHAB Distribution … SKIPPED
[INFO] ------------------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 08:12 min
[INFO] Finished at: 2016-10-09T17:18:13+02:00
[INFO] Final Memory: 310M/535M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.eclipse.tycho:tycho-compiler-plugin:0.22.0:compile (default-compile) on project org.openhab.binding.homematic: Compilation failure: Compilation failure:
[ERROR] /Users/carl/ontwikkelingen/openhab/install/openhab2-master/git/openhab/bundles/binding/org.openhab.binding.homematic/src/main/java/org/openhab/binding/homematic/internal/communicator/client/[82]
[ERROR] “version”, StringUtils.defaultIfBlank(version, “unknown”));
[ERROR] ^^^^^^^^^^^^^^
[ERROR] The method defaultIfBlank(String, String) is undefined for the type StringUtils
[ERROR] 1 problem (1 error)

Error was (probably) caused by a stale ~/Library/Java/Extensions/commons-lang-2.4.jar.
In Eclipse this problem can be revealed by right-clicking the offending class in the source file (in this case StringUtils) and choosing “Open Declaration”.