diff --git a/CMakeLists.txt b/CMakeLists.txt
index f01ca92..980c023 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,7 +2,7 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at https://mozilla.org/MPL/2.0/.
 
-cmake_minimum_required(VERSION 3.30)
+cmake_minimum_required(VERSION 4.0.0)
 project(Katja LANGUAGES CXX)
 
 include(CTest)
@@ -12,14 +12,11 @@ option(KATJA_BUILD_TUI "Build text user interface" ON)
 
 set(CMAKE_EXPORT_COMPILE_COMMANDS 1)
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
-set(CMAKE_CXX_STANDARD 20)
-set(CMAKE_CXX_MODULE_STD 1)
+set(CMAKE_CXX_STANDARD 23)
 
-add_library(katja
-	katja/database.cpp include/katja/database.hpp
-	katja/sbo.cpp include/katja/sbo.hpp
-	katja/repository.cpp include/katja/repository.hpp
-)
+add_library(katja)
+target_sources(katja PUBLIC FILE_SET all_my_modules TYPE CXX_MODULES FILES
+	katja/database.cpp katja/repository.cpp katja/sbo.cpp)
 include_directories(include ${Boost_INCLUDE_DIR})
 
 if(KATJA_BUILD_TUI)
diff --git a/cli/component.cpp b/cli/component.cpp
index b33be7a..6735077 100644
--- a/cli/component.cpp
+++ b/cli/component.cpp
@@ -12,9 +12,9 @@ module;
 #include <ftxui/component/component.hpp>
 #include <ftxui/dom/elements.hpp>
 
-#include "katja/repository.hpp"
+import katja.repository;
 
-export module component;
+export module katja.component;
 
 export namespace katja
 {
diff --git a/cli/main.cpp b/cli/main.cpp
index d0bf8b7..5502800 100644
--- a/cli/main.cpp
+++ b/cli/main.cpp
@@ -3,17 +3,20 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  */
+module;
+
 #include <filesystem>
+#include <memory>
 
 #include <ftxui/component/screen_interactive.hpp>
 #include <ftxui/dom/elements.hpp>
 #include <ftxui/component/component.hpp>
 #include <toml.hpp>
 
-#include "katja/sbo.hpp"
-#include "katja/database.hpp"
-
-import page;
+import katja.database;
+import katja.repository;
+import katja.sbo;
+import katja.page;
 
 int main(int argc, const char **argv)
 {
diff --git a/cli/page.cpp b/cli/page.cpp
index 617ee07..44b7e73 100644
--- a/cli/page.cpp
+++ b/cli/page.cpp
@@ -9,11 +9,12 @@ module;
 
 #include <ftxui/component/component.hpp>
 
-#include "katja/repository.hpp"
+import katja.database;
+import katja.repository;
 
-export module page;
+export module katja.page;
 
-import component;
+import katja.component;
 
 export namespace katja
 {
diff --git a/include/katja/database.hpp b/include/katja/database.hpp
deleted file mode 100644
index ca85ab1..0000000
--- a/include/katja/database.hpp
+++ /dev/null
@@ -1,39 +0,0 @@
-/*
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at https://mozilla.org/MPL/2.0/.
- */
-#pragma once
-
-#include <string>
-#include <map>
-
-namespace katja
-{
-    constexpr const char *database = "/var/lib/pkgtools/packages";
-
-    class database_package
-    {
-        database_package(std::string&& name, std::string&& version,
-                std::string&& architecture, std::string&& build_tag);
-
-        static database_package create_database_package(const std::string& fullname);
-
-    public:
-        const std::string name;
-        const std::string version;
-        const std::string architecture;
-        const std::string build_tag;
-
-        database_package(const std::string& fullname);
-
-        bool operator<(const database_package& that) const;
-        bool operator>(const database_package& that) const;
-
-        std::string to_string() const;
-    };
-
-    using package_database = std::multimap<std::string, database_package>;
-
-    package_database read_installed_database();
-}
diff --git a/include/katja/repository.hpp b/include/katja/repository.hpp
deleted file mode 100644
index cde9ca0..0000000
--- a/include/katja/repository.hpp
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at https://mozilla.org/MPL/2.0/.
- */
-#pragma once
-
-#include <string>
-#include <vector>
-
-#include "katja/database.hpp"
-
-namespace katja
-{
-    struct package_identifier
-    {
-        const std::string name;
-        const std::string version;
-        const std::string architecture;
-        const std::string data;
-
-        std::string to_string() const;
-    };
-
-    class repository
-    {
-    public:
-        virtual std::vector<package_identifier> get_updates(const package_database& database) = 0;
-        virtual std::vector<package_identifier> search_names(const std::string& architecture,
-                const std::string& needle) = 0;
-    };
-}
diff --git a/include/katja/sbo.hpp b/include/katja/sbo.hpp
deleted file mode 100644
index ba46509..0000000
--- a/include/katja/sbo.hpp
+++ /dev/null
@@ -1,44 +0,0 @@
-/*
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at https://mozilla.org/MPL/2.0/.
- */
-#pragma once
-
-#include <string>
-#include <vector>
-#include <filesystem>
-#include <optional>
-
-#include "katja/repository.hpp"
-
-namespace katja
-{
-    struct info_file
-    {
-        const std::string program_name;
-        const std::string version;
-        const std::string homepage;
-        const std::string email;
-        const std::string maintainer;
-
-        info_file(const std::string& program_name, const std::string& version,
-                const std::string homepage, const std::string& email, const std::string& maintainer);
-
-        package_identifier identifier_for(const std::string& architecture);
-    };
-
-    class sbo_repository final : public repository
-    {
-        std::map<std::string, std::filesystem::path> info_paths;
-
-    public:
-        sbo_repository(const std::filesystem::path& repository_path);
-
-        std::vector<package_identifier> get_updates(const package_database& database) override;
-        std::vector<package_identifier> search_names(const std::string& architecture,
-                const std::string& needle) override;
-    };
-
-    std::optional<info_file> read_slackbuild_info(const std::filesystem::path& info_filepath);
-}
diff --git a/katja/database.cpp b/katja/database.cpp
index 4f4b5b8..23cb6ca 100644
--- a/katja/database.cpp
+++ b/katja/database.cpp
@@ -3,84 +3,101 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  */
-#include "katja/database.hpp"
+module;
 
+#include <string>
+#include <map>
 #include <filesystem>
 
-namespace katja
+export module katja.database;
+
+export namespace katja
 {
-    database_package database_package::create_database_package(const std::string& fullname)
+    constexpr const char *database = "/var/lib/pkgtools/packages";
+
+    class database_package
     {
-        std::string::const_reverse_iterator begin_iterator = std::crbegin(fullname);
-        std::string::const_reverse_iterator end_iterator = begin_iterator;
-        int minus_counter = 0;
-
-        std::string build_tag;
-        std::string architecture;
-        std::string version;
-
-        for (; begin_iterator != std::crend(fullname) && minus_counter < 3; ++begin_iterator)
+        database_package(std::string&& name, std::string&& version,
+                    std::string&& architecture, std::string&& build_tag)
+            : name(name), version(version), architecture(architecture), build_tag(build_tag)
         {
-            if (*begin_iterator == '-')
-            {
-                if (minus_counter == 0)
-                {
-                    build_tag = std::string(begin_iterator.base(), end_iterator.base());
-                }
-                else if (minus_counter == 1)
-                {
-                    architecture = std::string(begin_iterator.base(), end_iterator.base());
-                }
-                else if (minus_counter == 2)
-                {
-                    version = std::string(begin_iterator.base(), end_iterator.base());
-                }
-                end_iterator = begin_iterator + 1;
-                ++minus_counter;
-            }
         }
-        return database_package(std::string(fullname.cbegin(), end_iterator.base()),
-                std::move(version), std::move(architecture), std::move(build_tag));
-    }
 
-    database_package::database_package(std::string&& name, std::string&& version,
-                std::string&& architecture, std::string&& build_tag)
-        : name(name), version(version), architecture(architecture), build_tag(build_tag)
-    {
-    }
+        static database_package create_database_package(const std::string& fullname)
+        {
+            std::string::const_reverse_iterator begin_iterator = std::crbegin(fullname);
+            std::string::const_reverse_iterator end_iterator = begin_iterator;
+            int minus_counter = 0;
 
-    database_package::database_package(const std::string& fullname)
-        : database_package(create_database_package(fullname))
-    {
-    }
+            std::string build_tag;
+            std::string architecture;
+            std::string version;
 
-    bool database_package::operator<(const database_package& that) const
-    {
-        return this->name < that.name;
-    }
+            for (; begin_iterator != std::crend(fullname) && minus_counter < 3; ++begin_iterator)
+            {
+                if (*begin_iterator == '-')
+                {
+                    if (minus_counter == 0)
+                    {
+                        build_tag = std::string(begin_iterator.base(), end_iterator.base());
+                    }
+                    else if (minus_counter == 1)
+                    {
+                        architecture = std::string(begin_iterator.base(), end_iterator.base());
+                    }
+                    else if (minus_counter == 2)
+                    {
+                        version = std::string(begin_iterator.base(), end_iterator.base());
+                    }
+                    end_iterator = begin_iterator + 1;
+                    ++minus_counter;
+                }
+            }
+            return database_package(std::string(fullname.cbegin(), end_iterator.base()),
+                    std::move(version), std::move(architecture), std::move(build_tag));
+        }
 
-    bool database_package::operator>(const database_package& that) const
-    {
-        return this->name > that.name;
-    }
+    public:
+        const std::string name;
+        const std::string version;
+        const std::string architecture;
+        const std::string build_tag;
 
-    std::string database_package::to_string() const
-    {
-        std::string package_string;
-        const std::size_t total_size = this->name.size() + this->version.size()
-            + this->architecture.size() + this->build_tag.size() + 3;
+        database_package(const std::string& fullname)
+            : database_package(create_database_package(fullname))
+        {
+        }
 
-        package_string.reserve(total_size);
-        package_string.append(this->name);
-        package_string.push_back('-');
-        package_string.append(this->version);
-        package_string.push_back('-');
-        package_string.append(this->architecture);
-        package_string.push_back('-');
-        package_string.append(this->build_tag);
+        bool operator<(const database_package& that) const
+        {
+            return this->name < that.name;
+        }
 
-        return package_string;
-    }
+        bool operator>(const database_package& that) const
+        {
+            return this->name > that.name;
+        }
+
+        std::string to_string() const
+        {
+            std::string package_string;
+            const std::size_t total_size = this->name.size() + this->version.size()
+                + this->architecture.size() + this->build_tag.size() + 3;
+
+            package_string.reserve(total_size);
+            package_string.append(this->name);
+            package_string.push_back('-');
+            package_string.append(this->version);
+            package_string.push_back('-');
+            package_string.append(this->architecture);
+            package_string.push_back('-');
+            package_string.append(this->build_tag);
+
+            return package_string;
+        }
+    };
+
+    using package_database = std::multimap<std::string, database_package>;
 
     package_database read_installed_database()
     {
diff --git a/katja/repository.cpp b/katja/repository.cpp
index 270ffec..38d5411 100644
--- a/katja/repository.cpp
+++ b/katja/repository.cpp
@@ -3,25 +3,48 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  */
-#include "katja/repository.hpp"
+module;
 
-namespace katja
+#include <string>
+#include <vector>
+
+export module katja.repository;
+
+import katja.database;
+
+export namespace katja
 {
-    std::string package_identifier::to_string() const
+    struct package_identifier
     {
-        std::string identifier;
-        const std::size_t total_size = this->name.size() + this->version.size()
-            + this->architecture.size() + this->data.size() + 3;
+        const std::string name;
+        const std::string version;
+        const std::string architecture;
+        const std::string data;
 
-        identifier.reserve(total_size);
-        identifier.append(this->name);
-        identifier.push_back(';');
-        identifier.append(this->version);
-        identifier.push_back(';');
-        identifier.append(this->architecture);
-        identifier.push_back(';');
-        identifier.append(this->data);
+        std::string to_string() const
+        {
+            std::string identifier;
+            const std::size_t total_size = this->name.size() + this->version.size()
+                + this->architecture.size() + this->data.size() + 3;
 
-        return identifier;
-    }
+            identifier.reserve(total_size);
+            identifier.append(this->name);
+            identifier.push_back(';');
+            identifier.append(this->version);
+            identifier.push_back(';');
+            identifier.append(this->architecture);
+            identifier.push_back(';');
+            identifier.append(this->data);
+
+            return identifier;
+        }
+    };
+
+    class repository
+    {
+    public:
+        virtual std::vector<package_identifier> get_updates(const package_database& database) = 0;
+        virtual std::vector<package_identifier> search_names(const std::string& architecture,
+                const std::string& needle) = 0;
+    };
 }
diff --git a/katja/sbo.cpp b/katja/sbo.cpp
index b53d8ee..f84d030 100644
--- a/katja/sbo.cpp
+++ b/katja/sbo.cpp
@@ -3,14 +3,61 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  */
+module;
+
 #include <fstream>
+#include <string>
+#include <vector>
+#include <filesystem>
+#include <optional>
+#include <map>
 
 #include <boost/algorithm/string.hpp>
 
-#include "katja/sbo.hpp"
+export module katja.sbo;
+
+import katja.database;
+import katja.repository;
 
 namespace katja
 {
+    static
+    bool trim_info_line(std::string& info_value)
+    {
+        if (boost::algorithm::ends_with(info_value, "\""))
+        {
+            info_value.pop_back();
+            return false;
+        }
+        else if (boost::algorithm::ends_with(info_value, "\\"))
+        {
+            info_value.pop_back();
+            return true;
+        }
+        return false;
+    }
+
+    export struct info_file
+    {
+        const std::string program_name;
+        const std::string version;
+        const std::string homepage;
+        const std::string email;
+        const std::string maintainer;
+
+        info_file(const std::string& program_name, const std::string& version,
+                const std::string homepage, const std::string& email, const std::string& maintainer)
+            : program_name(program_name), version(version), homepage(homepage), email(email), maintainer(maintainer)
+        {
+        }
+
+        package_identifier identifier_for(const std::string& architecture)
+        {
+            return package_identifier{ this->program_name, this->version, architecture, "SBo" };
+        }
+    };
+    export std::optional<info_file> read_slackbuild_info(const std::filesystem::path& info_filepath);
+
     static
     void search_for_slackbuilds(std::map<std::string, std::filesystem::path>& info_files,
             const std::filesystem::path& directory)
@@ -50,76 +97,58 @@ namespace katja
             }
         }
     }
+}
 
-    info_file::info_file(const std::string& program_name, const std::string& version,
-            const std::string homepage, const std::string& email, const std::string& maintainer)
-        : program_name(program_name), version(version), homepage(homepage), email(email), maintainer(maintainer)
+export namespace katja
+{
+    class sbo_repository final : public repository
     {
-    }
+        std::map<std::string, std::filesystem::path> info_paths;
 
-    package_identifier info_file::identifier_for(const std::string& architecture)
-    {
-        return package_identifier{ this->program_name, this->version, architecture, "SBo" };
-    }
-
-    sbo_repository::sbo_repository(const std::filesystem::path& repository_path)
-    {
-        search_for_slackbuilds(this->info_paths, repository_path);
-    }
-
-    std::vector<package_identifier> sbo_repository::get_updates(const package_database& database)
-    {
-        std::vector<package_identifier> identifiers;
-
-        for (const auto& [package_name, package] : database)
+    public:
+        sbo_repository(const std::filesystem::path& repository_path)
         {
-            auto looked_up_info_path = this->info_paths.find(package_name);
+            search_for_slackbuilds(this->info_paths, repository_path);
+        }
 
-            if (looked_up_info_path != this->info_paths.cend())
+        std::vector<package_identifier> get_updates(const package_database& database) override
+        {
+            std::vector<package_identifier> identifiers;
+
+            for (const auto& [package_name, package] : database)
             {
-                auto slackbuild_info = read_slackbuild_info(looked_up_info_path->second);
+                auto looked_up_info_path = this->info_paths.find(package_name);
 
-                if (slackbuild_info.has_value() && slackbuild_info.value().version != package.version)
+                if (looked_up_info_path != this->info_paths.cend())
                 {
-                    identifiers.push_back(slackbuild_info->identifier_for(package.architecture));
+                    auto slackbuild_info = read_slackbuild_info(looked_up_info_path->second);
+
+                    if (slackbuild_info.has_value() && slackbuild_info.value().version != package.version)
+                    {
+                        identifiers.push_back(slackbuild_info->identifier_for(package.architecture));
+                    }
                 }
             }
+            return identifiers;
         }
-        return identifiers;
-    }
 
-    std::vector<package_identifier> sbo_repository::search_names(const std::string& architecture,
-            const std::string& needle)
-    {
-        std::vector<package_identifier> identifiers;
-
-        for (const auto& [package_name, info_path] : this->info_paths)
+        std::vector<package_identifier> search_names(const std::string& architecture,
+                const std::string& needle) override
         {
-            if (package_name.find(needle) != std::string::npos)
+            std::vector<package_identifier> identifiers;
+
+            for (const auto& [package_name, info_path] : this->info_paths)
             {
-                auto slackbuild_info = read_slackbuild_info(info_path);
+                if (package_name.find(needle) != std::string::npos)
+                {
+                    auto slackbuild_info = read_slackbuild_info(info_path);
 
-                identifiers.push_back(slackbuild_info->identifier_for(architecture));
+                    identifiers.push_back(slackbuild_info->identifier_for(architecture));
+                }
             }
+            return identifiers;
         }
-        return identifiers;
-    }
-
-    static
-    bool trim_info_line(std::string& info_value)
-    {
-        if (boost::algorithm::ends_with(info_value, "\""))
-        {
-            info_value.pop_back();
-            return false;
-        }
-        else if (boost::algorithm::ends_with(info_value, "\\"))
-        {
-            info_value.pop_back();
-            return true;
-        }
-        return false;
-    }
+    };
 
     std::optional<info_file> read_slackbuild_info(const std::filesystem::path& info_filepath)
     {
diff --git a/tests/database.cpp b/tests/database.cpp
index d2651c8..ed764c8 100644
--- a/tests/database.cpp
+++ b/tests/database.cpp
@@ -6,7 +6,7 @@
 #define BOOST_TEST_MODULE database tests
 
 #include <boost/test/unit_test.hpp>
-#include "katja/database.hpp"
+import katja.database;
 
 BOOST_AUTO_TEST_CASE(generate_package_identifier)
 {
diff --git a/tests/repository.cpp b/tests/repository.cpp
index bb1d6c7..f025ef2 100644
--- a/tests/repository.cpp
+++ b/tests/repository.cpp
@@ -6,7 +6,7 @@
 #define BOOST_TEST_MODULE repository tests
 
 #include <boost/test/unit_test.hpp>
-#include "katja/repository.hpp"
+import katja.repository;
 
 BOOST_AUTO_TEST_CASE(construct_valid_database_package)
 {