GWT 2.8.0-beta1 included/forked in which Vaadin release?

Does Vaadin 7.6.4 include the forked contents of GWT 2.8.0-beta1?

If it does, how long has it been part of Vaadin?  

No it doesn't.

As far as I can recall, the fundamental problem is that GWT 2.8 is no longer Java 6 compatible whereas Vaadin 7 should be. Therefore, Vaadin 7 uses a slightly modified fork of GWT 2.7 (available at https://github.com/vaadin/gwt and in Maven Central as com.vaadin.external.gwt:gwt-*:2.7.0.vaadin3 .

Note also that Vaadin JARs repackage GWT classes so that vaadin-client and vaadin-client-compiler each contains a (different) big part of gwt-dev and and vaadin-shared and vaadin-server contain others (mostly from gwt-user and gwt-elemental). One of the reasons for this is that having some GWT classes in the deployable artifacts caused those not to deploy on some application servers that are supported by Vaadin. This might or might not be a problem nowadays.

We are now looking into reorganizing our use of GWT so that the GWT classes would be in separate JARs that you could exclude as dependencies and override with another compatible version, and in the longer term I hope you'd be able to use official GWT JARs as dependencies.

I´ve a problem related with this issue: I want to use Vaangular addon with Liferay DXP (i.e. OSGi). Vaangular depends on Javascript plus addon that also depends on the gwt-user:jar:2.7.0.vaadin4 and the gwt-elemental:jar:2.7.0.vaadin4 jars.

Liferay DXP sends me this error:
org.osgi.framework.BundleException: Could not resolve module: javascriptplus-for-vaadin [652]
  Unresolved requirement: Import-Package: com.google.gwt.core.client

The problem is that these jars are not OSGi and they missed the MANIFEST file (as the rest of Vaadin jar are OSGi compatible). I´m using Vaadin 7.7.6.

Any idea how can I solve this problem?