for (final Artifact a : artifacts) {
                if (a.getName().equals(artifact.getName()) && !a.getVersion().equals(artifact.getVersion())) {
                    try {
                        pluginHelper.deleteInstalledArtifact(a);
                    } catch (final Exception e) {
                        logger.warn("Failed to delete {}", a.getFileName(), e);
                    }
                }
            }
        }).start();

        if (proxy != null && !Proxy.NO_PROXY.equals(proxy)) {
            request.proxy(proxy);
        }
        return request;
    }

    public void deleteInstalledArtifact(final Artifact artifact) {
        final String fileName = artifact.getFileName();
        final Path jarPath = Paths.get(ResourceUtil.getPluginPath().toString(), fileName);
        if (!Files.exists(jarPath)) {