eZ\Publish\Core\REST\Server\Controller\Content::createDraftFromVersion PHP Method

    public function createDraftFromVersion($contentId, $versionNumber)
    {
        $contentInfo = $this->repository->getContentService()->loadContentInfo($contentId);
        $contentType = $this->repository->getContentTypeService()->loadContentType($contentInfo->contentTypeId);
        $contentDraft = $this->repository->getContentService()->createContentDraft($contentInfo, $this->repository->getContentService()->loadVersionInfo($contentInfo, $versionNumber));
        return new Values\CreatedVersion(array('version' => new Values\Version($contentDraft, $contentType, $this->repository->getContentService()->loadRelations($contentDraft->getVersionInfo()))));
    }