diff --git a/lib/Slic3r/GUI.pm b/lib/Slic3r/GUI.pm
index 2082728cc..40cfcad89 100644
--- a/lib/Slic3r/GUI.pm
+++ b/lib/Slic3r/GUI.pm
@@ -101,11 +101,14 @@ sub OnInit {
     $self->{app_config}->set('version', $Slic3r::VERSION);
     $self->{app_config}->save;
 
-    Slic3r::PresetUpdater::init_vendors();
-
     # my $version_check = $self->{app_config}->get('version_check');
     $self->{preset_updater} = Slic3r::PresetUpdater->new($VERSION_ONLINE_EVENT, $self->{app_config});
-    my $slic3r_update = $self->{app_config}->slic3r_update_avail;
+    eval { $self->{preset_updater}->config_update($self->{app_config}) };
+    if ($@) {
+        warn $@ . "\n";
+        fatal_error(undef, $@);
+    }
+    # my $slic3r_update = $self->{app_config}->slic3r_update_avail;
 
     Slic3r::GUI::set_app_config($self->{app_config});
     Slic3r::GUI::load_language();
@@ -123,6 +126,7 @@ sub OnInit {
     Slic3r::GUI::set_preset_bundle($self->{preset_bundle});
     
     # application frame
+    print STDERR "Creating main frame...\n";
     Wx::Image::FindHandlerType(wxBITMAP_TYPE_PNG) || Wx::Image::AddHandler(Wx::PNGHandler->new);
     $self->{mainframe} = my $frame = Slic3r::GUI::MainFrame->new(
         # If set, the "Controller" tab for the control of the printer over serial line and the serial port settings are hidden.
@@ -145,20 +149,22 @@ sub OnInit {
     # before the UI was up and running.
     $self->CallAfter(sub {
         # XXX: recreate_GUI ???
-        if ($slic3r_update) {
-            # TODO
-        }
+        # if ($slic3r_update) {
+        #     # TODO
+        # }
         # XXX: ?
         if ($run_wizard) {
             # Run the config wizard, don't offer the "reset user profile" checkbox.
             Slic3r::GUI::config_wizard(1);
         }
 
-        # $self->{preset_updater}->download($self->{preset_bundle});
+        # TODO: call periodically?
+        $self->{preset_updater}->sync($self->{app_config}, $self->{preset_bundle});
     });
 
     # The following event is emited by the C++ menu implementation of application language change.
     EVT_COMMAND($self, -1, $LANGUAGE_CHANGE_EVENT, sub{
+        print STDERR "LANGUAGE_CHANGE_EVENT\n";
         $self->recreate_GUI;
     });
 
@@ -179,6 +185,7 @@ sub OnInit {
 }
 
 sub recreate_GUI{
+    print STDERR "recreate_GUI\n";
     my ($self) = @_;
     my $topwindow = $self->GetTopWindow();
     $self->{mainframe} = my $frame = Slic3r::GUI::MainFrame->new(
diff --git a/resources/profiles/PrusaResearch.ini b/resources/profiles/PrusaResearch.ini
index cf82855cf..0ca094880 100644
--- a/resources/profiles/PrusaResearch.ini
+++ b/resources/profiles/PrusaResearch.ini
@@ -8,8 +8,7 @@ name = Prusa Research
 config_version = 0.1.0
 # Where to get the updates from?
 # TODO: proper URL
-# config_update_url = https://raw.githubusercontent.com/prusa3d/Slic3r-settings/master/live/PrusaResearch.ini
-config_update_url = https://gist.githubusercontent.com/vojtechkral/4d8fd4a3b8699a01ec892c264178461c/raw/e9187c3e15ceaf1a90f29b7c43cf3ccc746140f0/PrusaResearch.ini
+config_update_url = https://raw.githubusercontent.com/vojtechkral/slic3r-settings-tmp/master/PrusaResearch
 
 # The printer models will be shown by the Configuration Wizard in this order,
 # also the first model installed & the first nozzle installed will be activated after install.
diff --git a/xs/src/libslic3r/utils.cpp b/xs/src/libslic3r/utils.cpp
index 703d5ff66..733757e25 100644
--- a/xs/src/libslic3r/utils.cpp
+++ b/xs/src/libslic3r/utils.cpp
@@ -119,7 +119,7 @@ static std::string g_data_dir;
 
 void set_data_dir(const std::string &dir)
 {
-    g_data_dir = dir + "-alpha";    // FIXME: Resolve backcompat problems
+    g_data_dir = dir;
 }
 
 const std::string& data_dir()
diff --git a/xs/src/semver/semver.c b/xs/src/semver/semver.c
index 68d18af09..a19354403 100644
--- a/xs/src/semver/semver.c
+++ b/xs/src/semver/semver.c
@@ -637,4 +637,4 @@ semver_copy(const semver_t *ver) {
     res.prerelease = strdup(ver->prerelease);
   }
   return res;
-}
\ No newline at end of file
+}
diff --git a/xs/src/slic3r/Config/Version.cpp b/xs/src/slic3r/Config/Version.cpp
index 8344e2822..dc09ac870 100644
--- a/xs/src/slic3r/Config/Version.cpp
+++ b/xs/src/slic3r/Config/Version.cpp
@@ -270,7 +270,7 @@ Semver Index::version() const
     return ver;
 }
 
-Index::const_iterator Index::find(const Semver &ver)
+Index::const_iterator Index::find(const Semver &ver) const
 { 
 	Version key;
 	key.config_version = ver;
@@ -282,22 +282,21 @@ Index::const_iterator Index::find(const Semver &ver)
 Index::const_iterator Index::recommended() const
 {
 	int idx = -1;
-	const_iterator highest = m_configs.end();
+	const_iterator highest = this->end();
 	for (const_iterator it = this->begin(); it != this->end(); ++ it)
 		if (it->is_current_slic3r_supported() &&
-			(highest == this->end() || highest->max_slic3r_version < it->max_slic3r_version))
+			(highest == this->end() || highest->config_version < it->config_version))
 			highest = it;
 	return highest;
 }
 
 std::vector<Index> Index::load_db()
 {
-    boost::filesystem::path data_dir   = boost::filesystem::path(Slic3r::data_dir());
-    boost::filesystem::path vendor_dir = data_dir / "vendor";
+    boost::filesystem::path cache_dir = boost::filesystem::path(Slic3r::data_dir()) / "cache";
 
     std::vector<Index> index_db;
     std::string errors_cummulative;
-	for (auto &dir_entry : boost::filesystem::directory_iterator(vendor_dir))
+	for (auto &dir_entry : boost::filesystem::directory_iterator(cache_dir))
         if (boost::filesystem::is_regular_file(dir_entry.status()) && boost::algorithm::iends_with(dir_entry.path().filename().string(), ".idx")) {
         	Index idx;
             try {
diff --git a/xs/src/slic3r/Config/Version.hpp b/xs/src/slic3r/Config/Version.hpp
index fb45c17eb..acb0ae460 100644
--- a/xs/src/slic3r/Config/Version.hpp
+++ b/xs/src/slic3r/Config/Version.hpp
@@ -65,7 +65,7 @@ public:
 
 	const_iterator				begin()   const { return m_configs.begin(); }
 	const_iterator				end()     const { return m_configs.end(); }
-	const_iterator 				find(const Semver &ver);
+	const_iterator 				find(const Semver &ver) const;
 	const std::vector<Version>& configs() const { return m_configs; }
 	// Finds a recommended config to be installed for the current Slic3r version.
 	// Returns configs().end() if such version does not exist in the index. This shall never happen
diff --git a/xs/src/slic3r/GUI/AppConfig.cpp b/xs/src/slic3r/GUI/AppConfig.cpp
index ee77f877a..d0f2f1019 100644
--- a/xs/src/slic3r/GUI/AppConfig.cpp
+++ b/xs/src/slic3r/GUI/AppConfig.cpp
@@ -46,11 +46,15 @@ void AppConfig::set_defaults()
         set("no_defaults", "1");
     if (get("show_incompatible_presets").empty())
         set("show_incompatible_presets", "0");
-    // Version check is enabled by default in the config, but it is not implemented yet.   // XXX
+
     if (get("version_check").empty())
         set("version_check", "1");
+    // TODO: proper URL
+    if (get("version_check_url").empty())
+        set("version_check_url", "https://gist.githubusercontent.com/vojtechkral/4d8fd4a3b8699a01ec892c264178461c/raw/e9187c3e15ceaf1a90f29b7c43cf3ccc746140f0/slic3rPE.version");
     if (get("preset_update").empty())
         set("preset_update", "1");
+
     // Use OpenGL 1.1 even if OpenGL 2.0 is available. This is mainly to support some buggy Intel HD Graphics drivers.
     // https://github.com/prusa3d/Slic3r/issues/233
     if (get("use_legacy_opengl").empty())
diff --git a/xs/src/slic3r/GUI/AppConfig.hpp b/xs/src/slic3r/GUI/AppConfig.hpp
index cac2759f1..ffda083ec 100644
--- a/xs/src/slic3r/GUI/AppConfig.hpp
+++ b/xs/src/slic3r/GUI/AppConfig.hpp
@@ -69,12 +69,13 @@ public:
 	void 				clear_section(const std::string &section)
 		{ m_storage[section].clear(); }
 
+	typedef std::map<std::string, std::map<std::string, std::set<std::string>>> VendorMap;
 	bool                get_variant(const std::string &vendor, const std::string &model, const std::string &variant) const;
 	void                set_variant(const std::string &vendor, const std::string &model, const std::string &variant, bool enable);
 	void                set_vendors(const AppConfig &from);
-	void 				set_vendors(const std::map<std::string, std::map<std::string, std::set<std::string>>> &vendors) { m_vendors = vendors; m_dirty = true; }
-	void 				set_vendors(std::map<std::string, std::map<std::string, std::set<std::string>>> &&vendors) { m_vendors = std::move(vendors); m_dirty = true; }
-	const std::map<std::string, std::map<std::string, std::set<std::string>>> vendors() const { return m_vendors; }
+	void 				set_vendors(const VendorMap &vendors) { m_vendors = vendors; m_dirty = true; }
+	void 				set_vendors(VendorMap &&vendors) { m_vendors = std::move(vendors); m_dirty = true; }
+	const VendorMap&    vendors() const { return m_vendors; }
 
 	// return recent/skein_directory or recent/config_directory or empty string.
 	std::string 		get_last_dir() const;
@@ -105,7 +106,7 @@ private:
 	// Map of section, name -> value
 	std::map<std::string, std::map<std::string, std::string>> 	m_storage;
 	// Map of enabled vendors / models / variants
-	std::map<std::string, std::map<std::string, std::set<std::string>>> m_vendors;
+	VendorMap                                                   m_vendors;
 	// Has any value been modified since the config.ini has been last saved or loaded?
 	bool														m_dirty;
 };
diff --git a/xs/src/slic3r/GUI/ConfigSnapshotDialog.cpp b/xs/src/slic3r/GUI/ConfigSnapshotDialog.cpp
index 5bc8b1012..0e0df15f2 100644
--- a/xs/src/slic3r/GUI/ConfigSnapshotDialog.cpp
+++ b/xs/src/slic3r/GUI/ConfigSnapshotDialog.cpp
@@ -105,9 +105,6 @@ ConfigSnapshotDialog::ConfigSnapshotDialog(const Config::SnapshotDB &snapshot_db
         html->SetFonts(font.GetFaceName(), font.GetFaceName(), size);
         html->SetBorders(2);
         std::string text = generate_html_page(snapshot_db);
-        FILE *file = ::fopen("d:\\temp\\configsnapshotdialog.html", "wt");
-        fwrite(text.data(), 1, text.size(), file);
-        fclose(file);
         html->SetPage(text.c_str());
         vsizer->Add(html, 1, wxEXPAND | wxALIGN_LEFT | wxRIGHT | wxBOTTOM, 0);
         html->Bind(wxEVT_HTML_LINK_CLICKED, &ConfigSnapshotDialog::onLinkClicked, this);
diff --git a/xs/src/slic3r/GUI/ConfigWizard.cpp b/xs/src/slic3r/GUI/ConfigWizard.cpp
index 30d1bf4e3..3b4b3f5e4 100644
--- a/xs/src/slic3r/GUI/ConfigWizard.cpp
+++ b/xs/src/slic3r/GUI/ConfigWizard.cpp
@@ -1,8 +1,8 @@
 #include "ConfigWizard_private.hpp"
 
+#include <iostream>   // XXX
 #include <algorithm>
 #include <utility>
-#include <boost/filesystem.hpp>
 
 #include <wx/settings.h>
 #include <wx/stattext.h>
@@ -17,7 +17,6 @@
 #include "GUI.hpp"
 #include "slic3r/Utils/PresetUpdater.hpp"
 
-namespace fs = boost::filesystem;
 
 namespace Slic3r {
 namespace GUI {
@@ -62,25 +61,25 @@ PrinterPicker::PrinterPicker(wxWindow *parent, const VendorProfile &vendor, cons
 	auto namefont = wxSystemSettings::GetFont(wxSYS_DEFAULT_GUI_FONT);
 	namefont.SetWeight(wxFONTWEIGHT_BOLD);
 
-	for (auto model = models.cbegin(); model != models.cend(); ++model) {
+	for (const auto &model : models) {
 		auto *panel = new wxPanel(this);
 		auto *sizer = new wxBoxSizer(wxVERTICAL);
 		panel->SetSizer(sizer);
 
-		auto *title = new wxStaticText(panel, wxID_ANY, model->name, wxDefaultPosition, wxDefaultSize, wxALIGN_LEFT);
+		auto *title = new wxStaticText(panel, wxID_ANY, model.name, wxDefaultPosition, wxDefaultSize, wxALIGN_LEFT);
 		title->SetFont(namefont);
 		sizer->Add(title, 0, wxBOTTOM, 3);
 
-		auto bitmap_file = wxString::Format("printers/%s_%s.png", vendor.id, model->id);
+		auto bitmap_file = wxString::Format("printers/%s_%s.png", vendor.id, model.id);
 		wxBitmap bitmap(GUI::from_u8(Slic3r::var(bitmap_file.ToStdString())), wxBITMAP_TYPE_PNG);
 		auto *bitmap_widget = new wxStaticBitmap(panel, wxID_ANY, bitmap);
 		sizer->Add(bitmap_widget, 0, wxBOTTOM, 3);
 
 		sizer->AddSpacer(20);
 
-		const auto model_id = model->id;
+		const auto model_id = model.id;
 
-		for (const auto &variant : model->variants) {
+		for (const auto &variant : model.variants) {
 			const auto variant_name = variant.name;
 			auto *cbox = new wxCheckBox(panel, wxID_ANY, wxString::Format("%s %s %s", variant.name, _(L("mm")), _(L("nozzle"))));
 			bool enabled = appconfig_vendors.get_variant("PrusaResearch", model_id, variant_name);
@@ -177,16 +176,18 @@ PageWelcome::PageWelcome(ConfigWizard *parent) :
 {
 	append_text(_(L("Hello, welcome to Slic3r Prusa Edition! TODO: This text.")));
 
-	const PresetBundle &bundle = wizard_p()->bundle_vendors;
-	const auto &vendors = bundle.vendors;
-	const auto vendor_prusa = std::find(vendors.cbegin(), vendors.cend(), VendorProfile("PrusaResearch"));
+	// const PresetBundle &bundle = wizard_p()->bundle_vendors;
+	// const auto &vendors = bundle.vendors;
+	const auto &vendors = wizard_p()->vendors;
+	// const auto vendor_prusa = std::find(vendors.cbegin(), vendors.cend(), VendorProfile("PrusaResearch"));
+	const auto vendor_prusa = vendors.find("PrusaResearch");
 
 	if (vendor_prusa != vendors.cend()) {
-		const auto &models = vendor_prusa->models;
+		const auto &models = vendor_prusa->second.models;
 
 		AppConfig &appconfig_vendors = this->wizard_p()->appconfig_vendors;
 
-		printer_picker = new PrinterPicker(this, *vendor_prusa, appconfig_vendors);
+		printer_picker = new PrinterPicker(this, vendor_prusa->second, appconfig_vendors);
 		printer_picker->Bind(EVT_PRINTER_PICK, [this, &appconfig_vendors](const PrinterPickerEvent &evt) {
 			appconfig_vendors.set_variant(evt.vendor_id, evt.model_id, evt.variant_name, evt.enable);
 			this->on_variant_checked();
@@ -248,14 +249,17 @@ PageVendors::PageVendors(ConfigWizard *parent) :
 {
 	append_text(_(L("Pick another vendor supported by Slic3r PE:")));
 
-	const PresetBundle &bundle = wizard_p()->bundle_vendors;
+	// const PresetBundle &bundle = wizard_p()->bundle_vendors;
+	// const auto &vendors = wizard_p()->vendors;
 	auto boldfont = wxSystemSettings::GetFont(wxSYS_DEFAULT_GUI_FONT);
 	boldfont.SetWeight(wxFONTWEIGHT_BOLD);
 
 	AppConfig &appconfig_vendors = this->wizard_p()->appconfig_vendors;
 	wxArrayString choices_vendors;
 
-	for (const auto &vendor : bundle.vendors) {
+	// for (const auto &vendor : vendors) {
+	for (const auto vendor_pair : wizard_p()->vendors) {
+		const auto &vendor = vendor_pair.second;
 		if (vendor.id == "PrusaResearch") { continue; }
 
 		auto *picker = new PrinterPicker(this, vendor, appconfig_vendors);
@@ -549,9 +553,25 @@ void ConfigWizardIndex::on_paint(wxPaintEvent & evt)
 void ConfigWizard::priv::load_vendors()
 {
 	const auto vendor_dir = fs::path(Slic3r::data_dir()) / "vendor";
+	const auto rsrc_vendor_dir = fs::path(resources_dir()) / "profiles";
+
+	// Load vendors from the "vendors" directory in datadir
 	for (fs::directory_iterator it(vendor_dir); it != fs::directory_iterator(); ++it) {
 		if (it->path().extension() == ".ini") {
-			bundle_vendors.load_configbundle(it->path().string(), PresetBundle::LOAD_CFGBUNDLE_VENDOR_ONLY);
+			auto vp = VendorProfile::from_ini(it->path());
+			vendors[vp.id] = std::move(vp);
+		}
+	}
+
+	// Additionally load up vendors from the application resources directory, but only those not seen in the datadir
+	for (fs::directory_iterator it(rsrc_vendor_dir); it != fs::directory_iterator(); ++it) {
+		if (it->path().extension() == ".ini") {
+			const auto id = it->path().stem().string();
+			if (vendors.find(id) == vendors.end()) {
+				auto vp = VendorProfile::from_ini(it->path());
+				vendors_rsrc[vp.id] = it->path();
+				vendors[vp.id] = std::move(vp);
+			}
 		}
 	}
 
@@ -624,11 +644,25 @@ void ConfigWizard::priv::apply_config(AppConfig *app_config, PresetBundle *prese
 	const bool is_custom_setup = page_welcome->page_next() == page_firmware;
 
 	if (! is_custom_setup) {
+		const auto enabled_vendors = appconfig_vendors.vendors();
+		for (const auto &vendor_rsrc : vendors_rsrc) {
+			const auto vendor = enabled_vendors.find(vendor_rsrc.first);
+			if (vendor == enabled_vendors.end()) { continue; }
+	
+			size_t size_sum = 0;
+			for (const auto &model : vendor->second) { size_sum += model.second.size(); }
+			if (size_sum == 0) { continue; }
+
+			// This vendor needs to be installed
+			PresetBundle::install_vendor_configbundle(vendor_rsrc.second);
+		}
+
 		app_config->set_vendors(appconfig_vendors);
 		app_config->set("version_check", page_update->version_check ? "1" : "0");
 		app_config->set("preset_update", page_update->preset_update ? "1" : "0");
 		if (fresh_start)
 			app_config->reset_selections();
+		// ^ TODO: replace with appropriate printer selection
 		preset_bundle->load_presets(*app_config);
 	} else {
 		for (ConfigWizardPage *page = page_firmware; page != nullptr; page = page->page_next()) {
diff --git a/xs/src/slic3r/GUI/ConfigWizard_private.hpp b/xs/src/slic3r/GUI/ConfigWizard_private.hpp
index 6881f6f55..32d038acf 100644
--- a/xs/src/slic3r/GUI/ConfigWizard_private.hpp
+++ b/xs/src/slic3r/GUI/ConfigWizard_private.hpp
@@ -4,6 +4,9 @@
 #include "ConfigWizard.hpp"
 
 #include <vector>
+#include <set>
+#include <unordered_map>
+#include <boost/filesystem.hpp>
 
 #include <wx/sizer.h>
 #include <wx/panel.h>
@@ -13,13 +16,15 @@
 
 #include "libslic3r/PrintConfig.hpp"
 #include "AppConfig.hpp"
-#include "PresetBundle.hpp"
+#include "Preset.hpp"
 #include "BedShapeDialog.hpp"
 
+namespace fs = boost::filesystem;
 
 namespace Slic3r {
 namespace GUI {
 
+// typedef std::unordered_map<std::string, VendorProfile> VendorMap;
 
 enum {
 	CONTENT_WIDTH = 500,
@@ -167,8 +172,9 @@ private:
 struct ConfigWizard::priv
 {
 	ConfigWizard *q;
-	AppConfig appconfig_vendors;
-	PresetBundle bundle_vendors;
+	AppConfig appconfig_vendors;    // TODO: use order-preserving container
+	std::unordered_map<std::string, VendorProfile> vendors;   // TODO: just set?
+	std::unordered_map<std::string, fs::path> vendors_rsrc;
 	std::unique_ptr<DynamicPrintConfig> custom_config;
 
 	wxBoxSizer *topsizer = nullptr;
diff --git a/xs/src/slic3r/GUI/Preset.cpp b/xs/src/slic3r/GUI/Preset.cpp
index 853c229ff..1e74952c4 100644
--- a/xs/src/slic3r/GUI/Preset.cpp
+++ b/xs/src/slic3r/GUI/Preset.cpp
@@ -5,6 +5,8 @@
 #include "AppConfig.hpp"
 
 #include <fstream>
+#include <stdexcept>
+#include <boost/format.hpp>
 #include <boost/filesystem.hpp>
 #include <boost/filesystem/fstream.hpp>
 #include <boost/algorithm/string/predicate.hpp>
@@ -75,6 +77,11 @@ VendorProfile VendorProfile::from_ini(const ptree &tree, const boost::filesystem
 {
     static const std::string printer_model_key = "printer_model:";
     const std::string id = path.stem().string();
+
+    if (! boost::filesystem::exists(path)) {
+        throw std::runtime_error((boost::format("Cannot load Vendor Config Bundle `%1%`: File not found: `%2%`.") % id % path).str());
+    }
+
     VendorProfile res(id);
 
     auto get_or_throw = [&](const ptree &tree, const std::string &key) -> ptree::const_assoc_iterator
diff --git a/xs/src/slic3r/GUI/Preset.hpp b/xs/src/slic3r/GUI/Preset.hpp
index 08caf4d4e..5f9dfa186 100644
--- a/xs/src/slic3r/GUI/Preset.hpp
+++ b/xs/src/slic3r/GUI/Preset.hpp
@@ -59,7 +59,8 @@ public:
     };
     std::vector<PrinterModel>          models;
 
-    VendorProfile(std::string id) : id(std::move(id)), config_version(0, 0, 0) {}
+    VendorProfile() {}
+    VendorProfile(std::string id) : id(std::move(id)) {}
 
     static VendorProfile from_ini(const boost::filesystem::path &path, bool load_all=true);
     static VendorProfile from_ini(const boost::property_tree::ptree &tree, const boost::filesystem::path &path, bool load_all=true);
diff --git a/xs/src/slic3r/GUI/PresetBundle.cpp b/xs/src/slic3r/GUI/PresetBundle.cpp
index 244915864..27dee6383 100644
--- a/xs/src/slic3r/GUI/PresetBundle.cpp
+++ b/xs/src/slic3r/GUI/PresetBundle.cpp
@@ -713,8 +713,7 @@ size_t PresetBundle::load_configbundle(const std::string &path, unsigned int fla
 
     const VendorProfile *vendor_profile = nullptr;
     if (flags & (LOAD_CFGBNDLE_SYSTEM | LOAD_CFGBUNDLE_VENDOR_ONLY)) {
-        boost::filesystem::path fspath(path);
-        auto vp = VendorProfile::from_ini(tree, fspath.stem().string());
+        auto vp = VendorProfile::from_ini(tree, path);
         if (vp.num_variants() == 0)
             return 0;
         vendor_profile = &(*this->vendors.insert(vp).first);
diff --git a/xs/src/slic3r/Utils/PresetUpdater.cpp b/xs/src/slic3r/Utils/PresetUpdater.cpp
index a16a6d889..257c7f552 100644
--- a/xs/src/slic3r/Utils/PresetUpdater.cpp
+++ b/xs/src/slic3r/Utils/PresetUpdater.cpp
@@ -1,61 +1,148 @@
 #include "PresetUpdater.hpp"
 
+#include <iostream>    // XXX
+#include <algorithm>
 #include <thread>
+#include <stack>
+#include <stdexcept>
+#include <boost/format.hpp>
 #include <boost/algorithm/string.hpp>
 #include <boost/filesystem.hpp>
 #include <boost/filesystem/fstream.hpp>
 
 #include <wx/app.h>
 #include <wx/event.h>
+#include <wx/msgdlg.h>
 
 #include "libslic3r/Utils.hpp"
 #include "slic3r/GUI/GUI.hpp"
 #include "slic3r/GUI/PresetBundle.hpp"
 #include "slic3r/Utils/Http.hpp"
-#include "slic3r/Utils/Semver.hpp"
+#include "slic3r/Config/Version.hpp"
+#include "slic3r/Config/Snapshot.hpp"
 
 namespace fs = boost::filesystem;
+using Slic3r::GUI::Config::Index;
+using Slic3r::GUI::Config::Version;
+using Slic3r::GUI::Config::Snapshot;
+using Slic3r::GUI::Config::SnapshotDB;
 
 
 namespace Slic3r {
 
 
-// TODO: proper URL
-// TODO: Actually, use index
-static const std::string SLIC3R_VERSION_URL = "https://gist.githubusercontent.com/vojtechkral/4d8fd4a3b8699a01ec892c264178461c/raw/e9187c3e15ceaf1a90f29b7c43cf3ccc746140f0/slic3rPE.version";
 enum {
 	SLIC3R_VERSION_BODY_MAX = 256,
 };
 
+static const char *INDEX_FILENAME = "index.idx";
+static const char *TMP_EXTENSION = ".download";
+
+
+struct Update
+{
+	fs::path source;
+	fs::path target;
+	Version version;
+
+	Update(fs::path &&source, const fs::path &target, const Version &version) :
+		source(source),
+		target(std::move(target)),
+		version(version)
+	{}
+
+	std::string name() { return source.stem().string(); }
+};
+
+typedef std::vector<Update> Updates;
+
+
 struct PresetUpdater::priv
 {
 	int version_online_event;
-	bool version_check;
-	bool preset_update;
+	std::vector<Index> index_db;
+
+	bool enabled_version_check;
+	bool enabled_config_update;
+	std::string version_check_url;
 
 	fs::path cache_path;
+	fs::path rsrc_path;
+	fs::path vendor_path;
+
 	bool cancel;
 	std::thread thread;
 
-	priv(int event);
+	priv(int event, AppConfig *app_config);
 
-	void download(const std::set<VendorProfile> vendors) const;
+	void set_download_prefs(AppConfig *app_config);
+	bool get_file(const std::string &url, const fs::path &target_path) const;
+	void prune_tmps() const;
+	void sync_version() const;
+	void sync_config(const std::set<VendorProfile> vendors) const;
+
+	void check_install_indices() const;
+	Updates config_update() const;
 };
 
-PresetUpdater::priv::priv(int event) :
+PresetUpdater::priv::priv(int event, AppConfig *app_config) :
 	version_online_event(event),
-	version_check(false),
-	preset_update(false),
 	cache_path(fs::path(Slic3r::data_dir()) / "cache"),
+	rsrc_path(fs::path(resources_dir()) / "profiles"),
+	vendor_path(fs::path(Slic3r::data_dir()) / "vendor"),
 	cancel(false)
-{}
-
-void PresetUpdater::priv::download(const std::set<VendorProfile> vendors) const
 {
-	if (!version_check) { return; }
+	set_download_prefs(app_config);
+	check_install_indices();
+	index_db = std::move(Index::load_db());
+}
 
-	// Download current Slic3r version
-	Http::get(SLIC3R_VERSION_URL)
+void PresetUpdater::priv::set_download_prefs(AppConfig *app_config)
+{
+	enabled_version_check = app_config->get("version_check") == "1";
+	version_check_url = app_config->get("version_check_url");
+	enabled_config_update = app_config->get("preset_update") == "1";
+}
+
+bool PresetUpdater::priv::get_file(const std::string &url, const fs::path &target_path) const
+{
+	std::cerr << "get_file(): " << url << " -> " << target_path << std::endl;
+
+	// TODO: Proper caching
+
+	bool res = false;
+	fs::path tmp_path = target_path;
+	tmp_path += TMP_EXTENSION;
+
+	Http::get(url)
+		.on_progress([this](Http::Progress, bool &cancel) {
+			if (cancel) { cancel = true; }
+		})
+		.on_complete([&](std::string body, unsigned http_status) {
+			fs::fstream file(tmp_path, std::ios::out | std::ios::binary | std::ios::trunc);
+			file.write(body.c_str(), body.size());
+			fs::rename(tmp_path, target_path);
+			res = true;
+		})
+		.perform_sync();
+
+	return res;
+}
+
+void PresetUpdater::priv::prune_tmps() const
+{
+	for (fs::directory_iterator it(cache_path); it != fs::directory_iterator(); ++it) {
+		if (it->path().extension() == TMP_EXTENSION) {
+			fs::remove(it->path());
+		}
+	}
+}
+
+void PresetUpdater::priv::sync_version() const
+{
+	if (! enabled_version_check) { return; }
+
+	Http::get(version_check_url)
 		.size_limit(SLIC3R_VERSION_BODY_MAX)
 		.on_progress([this](Http::Progress, bool &cancel) {
 			cancel = this->cancel;
@@ -67,38 +154,126 @@ void PresetUpdater::priv::download(const std::set<VendorProfile> vendors) const
 			GUI::get_app()->QueueEvent(evt);
 		})
 		.perform_sync();
+}
 
-	if (!preset_update) { return; }
+void PresetUpdater::priv::sync_config(const std::set<VendorProfile> vendors) const
+{
+	std::cerr << "sync_config()" << std::endl;
+
+	if (!enabled_config_update) { return; }
 
 	// Donwload vendor preset bundles
-	for (const auto &vendor : vendors) {
+	for (const auto &index : index_db) {
 		if (cancel) { return; }
 
-		// TODO: Proper caching
+		std::cerr << "Index: " << index.vendor() << std::endl;
 
-		auto target_path = cache_path / vendor.id;
-		target_path += ".ini";
+		const auto vendor_it = vendors.find(VendorProfile(index.vendor()));
+		if (vendor_it == vendors.end()) { continue; }
 
-		Http::get(vendor.config_update_url)
-			.on_progress([this](Http::Progress, bool &cancel) {
-				cancel = this->cancel;
-			})
-			.on_complete([&](std::string body, unsigned http_status) {
-				fs::fstream file(target_path, std::ios::out | std::ios::binary | std::ios::trunc);
-				file.write(body.c_str(), body.size());
-			})
-			.perform_sync();
+		const VendorProfile &vendor = *vendor_it;
+		if (vendor.config_update_url.empty()) { continue; }
+
+		// Download a fresh index
+		const auto idx_url = vendor.config_update_url + "/" + INDEX_FILENAME;
+		const auto idx_path = cache_path / (vendor.id + ".idx");
+		if (! get_file(idx_url, idx_path)) { continue; }
+		if (cancel) { return; }
+
+		std::cerr << "Got a new index: " << idx_path << std::endl;
+
+		// Load the fresh index up
+		Index new_index;
+		new_index.load(idx_path);
+
+		// See if a there's a new version to download
+		const auto recommended_it = new_index.recommended();
+		if (recommended_it == new_index.end()) { continue; }
+		const auto recommended = recommended_it->config_version;
+
+		std::cerr << "Current vendor version: " << vendor.config_version.to_string() << std::endl;
+		std::cerr << "Recommended version:\t" << recommended.to_string() << std::endl;
+
+		if (vendor.config_version >= recommended) { continue; }
+
+		// Download a fresh bundle
+		const auto bundle_url = (boost::format("%1%/%2%.ini") % vendor.config_update_url % recommended.to_string()).str();
+		const auto bundle_path = cache_path / (vendor.id + ".ini");
+		if (! get_file(bundle_url, bundle_path)) { continue; }
+		if (cancel) { return; }
+
+		std::cerr << "Got a new bundle: " << bundle_path << std::endl;
 	}
 }
 
-PresetUpdater::PresetUpdater(int version_online_event, AppConfig *app_config) :
-	p(new priv(version_online_event))
+void PresetUpdater::priv::check_install_indices() const
 {
-	p->preset_update = app_config->get("preset_update") == "1";
-	// preset_update implies version_check:
-	p->version_check = p->preset_update || app_config->get("version_check") == "1";
+	for (fs::directory_iterator it(rsrc_path); it != fs::directory_iterator(); ++it) {
+		const auto &path = it->path();
+		if (path.extension() == ".idx") {
+			const auto path_in_cache = cache_path / path.filename();
+
+			// TODO: compare versions
+			if (! fs::exists(path_in_cache)) {
+				fs::copy_file(path, path_in_cache, fs::copy_option::overwrite_if_exists);
+			}
+		}
+	}
 }
 
+Updates PresetUpdater::priv::config_update() const
+{
+	Updates updates;
+
+	for (const auto idx : index_db) {
+		const auto bundle_path = vendor_path / (idx.vendor() + ".ini");
+
+		if (! fs::exists(bundle_path)) {
+			continue;
+		}
+
+		// Perform a basic load and check the version
+		const auto vp = VendorProfile::from_ini(bundle_path, false);
+
+		const auto ver_current = idx.find(vp.config_version);
+		if (ver_current == idx.end()) {
+			// TODO: throw / ignore ?
+		}
+
+		const auto recommended = idx.recommended();
+		if (recommended == idx.end()) {
+			throw std::runtime_error((boost::format("Invalid index: `%1%`") % idx.vendor()).str());
+		}
+
+		if (! ver_current->is_current_slic3r_supported()) {
+
+			// TODO: Downgrade situation
+
+		} else if (recommended->config_version > ver_current->config_version) {
+			// Config bundle update situation
+
+			auto path_in_cache = cache_path / (idx.vendor() + ".ini");
+			if (! fs::exists(path_in_cache)) {
+				continue;
+			}
+
+			const auto cached_vp = VendorProfile::from_ini(path_in_cache, false);
+			if (cached_vp.config_version == recommended->config_version) {
+				updates.emplace_back(std::move(path_in_cache), bundle_path, *recommended);
+			} else {
+				// XXX: ?
+			}
+		}
+	}
+
+	return updates;
+}
+
+
+PresetUpdater::PresetUpdater(int version_online_event, AppConfig *app_config) :
+	p(new priv(version_online_event, app_config))
+{}
+
 
 // Public
 
@@ -110,8 +285,10 @@ PresetUpdater::~PresetUpdater()
 	}
 }
 
-void PresetUpdater::download(PresetBundle *preset_bundle)
+void PresetUpdater::sync(AppConfig *app_config, PresetBundle *preset_bundle)
 {
+	p->set_download_prefs(app_config);
+	if (!p->enabled_version_check && !p->enabled_config_update) { return; }
 
 	// Copy the whole vendors data for use in the background thread
 	// Unfortunatelly as of C++11, it needs to be copied again
@@ -119,23 +296,56 @@ void PresetUpdater::download(PresetBundle *preset_bundle)
 	std::set<VendorProfile> vendors = preset_bundle->vendors;
 
 	p->thread = std::move(std::thread([this, vendors]() {
-		this->p->download(std::move(vendors));
+		this->p->prune_tmps();
+		this->p->sync_version();
+		this->p->sync_config(std::move(vendors));
 	}));
 }
 
-void PresetUpdater::init_vendors()
+void PresetUpdater::config_update(AppConfig *app_config)
 {
-	const auto vendors_rources = fs::path(resources_dir()) / "profiles";
-	const auto vendors_data = fs::path(Slic3r::data_dir()) / "vendor";
+	if (! p->enabled_config_update) { return; }
 
-	for (fs::directory_iterator it(vendors_rources); it != fs::directory_iterator(); ++it) {
-		if (it->path().extension() == ".ini") {
-			auto vp = VendorProfile::from_ini(it->path(), false);
-			const auto path_in_data = vendors_data / it->path().filename();
+	const auto updates = p->config_update();
+	if (updates.size() > 0) {
+		const auto msg = _(L("Configuration update is available. Would you like to install it?"));
 
-			if (! fs::exists(path_in_data) || VendorProfile::from_ini(path_in_data, false).config_version < vp.config_version) {
-				// FIXME: update vendor bundle properly when snapshotting is ready
-				PresetBundle::install_vendor_configbundle(it->path());
+		auto ext_msg = _(L(
+			"Note that a full configuration snapshot will be created first. It can then be restored at any time "
+			"should there be a problem with the new version.\n\n"
+			"Updated configuration bundles:\n"
+		));
+
+		for (const auto &update : updates) {
+			ext_msg += update.target.stem().string() + " " + update.version.config_version.to_string();
+			if (! update.version.comment.empty()) {
+				ext_msg += std::string(" (") + update.version.comment + ")";
+			}
+			ext_msg += "\n";
+		}
+
+		wxMessageDialog dlg(NULL, msg, _(L("Configuration update")), wxYES_NO|wxCENTRE);
+		dlg.SetExtendedMessage(ext_msg);
+		const auto res = dlg.ShowModal();
+		std::cerr << "After modal" << std::endl;
+		if (res == wxID_YES) {
+			// User gave clearance, updates are go
+
+			SnapshotDB::singleton().take_snapshot(*app_config, Snapshot::SNAPSHOT_UPGRADE, "");
+
+			for (const auto &update : updates) {
+				fs::copy_file(update.source, update.target, fs::copy_option::overwrite_if_exists);
+
+				PresetBundle bundle;
+				bundle.load_configbundle(update.target.string(), PresetBundle::LOAD_CFGBNDLE_SYSTEM);
+
+				auto preset_remover = [](const Preset &preset) {
+					fs::remove(preset.file);
+				};
+
+				for (const auto &preset : bundle.prints) { preset_remover(preset); }
+				for (const auto &preset : bundle.filaments) { preset_remover(preset); }
+				for (const auto &preset : bundle.printers) { preset_remover(preset); }
 			}
 		}
 	}
diff --git a/xs/src/slic3r/Utils/PresetUpdater.hpp b/xs/src/slic3r/Utils/PresetUpdater.hpp
index b10c61784..966dd1464 100644
--- a/xs/src/slic3r/Utils/PresetUpdater.hpp
+++ b/xs/src/slic3r/Utils/PresetUpdater.hpp
@@ -19,9 +19,9 @@ public:
 	PresetUpdater &operator=(const PresetUpdater &) = delete;
 	~PresetUpdater();
 
-	void download(PresetBundle *preset_bundle);     // XXX
+	void sync(AppConfig *app_config, PresetBundle *preset_bundle);
 
-	static void init_vendors();
+	void config_update(AppConfig *app_config);
 private:
 	struct priv;
 	std::unique_ptr<priv> p;
diff --git a/xs/src/slic3r/Utils/Semver.hpp b/xs/src/slic3r/Utils/Semver.hpp
index 538a3f144..2a1bee0ed 100644
--- a/xs/src/slic3r/Utils/Semver.hpp
+++ b/xs/src/slic3r/Utils/Semver.hpp
@@ -11,7 +11,6 @@
 
 namespace Slic3r {
 
-// FIXME:: operators=: leak, return
 
 class Semver
 {
@@ -20,6 +19,8 @@ public:
 	struct Minor { const int i;  Minor(int i) : i(i) {} };
 	struct Patch { const int i;  Patch(int i) : i(i) {} };
 
+	Semver() : ver(semver_zero()) {}
+
 	Semver(int major, int minor, int patch,
 		boost::optional<std::string> metadata = boost::none,
 		boost::optional<std::string> prerelease = boost::none)
diff --git a/xs/xsp/Utils_PresetUpdater.xsp b/xs/xsp/Utils_PresetUpdater.xsp
index 1cb9f1c39..3a4d55a01 100644
--- a/xs/xsp/Utils_PresetUpdater.xsp
+++ b/xs/xsp/Utils_PresetUpdater.xsp
@@ -7,6 +7,6 @@
 
 %name{Slic3r::PresetUpdater} class PresetUpdater {
     PresetUpdater(int version_online_event, AppConfig *app_config);
-    void download(PresetBundle* preset_bundle);
-    static void init_vendors();
+    void sync(AppConfig *app_config, PresetBundle* preset_bundle);
+    void config_update(AppConfig *app_config);
 };