diff --git a/.github/workflows/php-psr.yml b/.github/workflows/php-psr.yml
index 6f2de99..abecdab 100644
--- a/.github/workflows/php-psr.yml
+++ b/.github/workflows/php-psr.yml
@@ -9,7 +9,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: [ '7.4' , '8.0' , '8.1' ]
+        php: [ '8.1' ]
     steps:
       - uses: actions/checkout@v2
         name: Checkout
diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index d20f815..9990748 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -9,7 +9,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: [ '7.4', '8.0', '8.1']
+        php: ['8.1']
     steps:
       - uses: actions/checkout@v2
         name: Checkout
diff --git a/composer.json b/composer.json
index 44280f9..0e3c4ef 100644
--- a/composer.json
+++ b/composer.json
@@ -4,7 +4,7 @@
   "type": "library",
   "license": "GPL-3.0-or-later",
   "require": {
-    "php": "7.4.* | 8.0.* | 8.1.* ",
+    "php": "8.1.* ",
     "nette/utils": "^v3.2.0",
     "nette/di": "^3.0.0",
     "nette/application": "^3.1.0",
diff --git a/src/DateTime/Period.php b/src/DateTime/Period.php
new file mode 100644
index 0000000..edc9e0b
--- /dev/null
+++ b/src/DateTime/Period.php
@@ -0,0 +1,61 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Fykosak\Utils\DateTime;
+
+class Period
+{
+    public function __construct(
+        public readonly \DateTimeImmutable $begin,
+        public readonly \DateTimeImmutable $end,
+    ) {
+        if ($this->begin > $this->end) {
+            throw new \LogicException();
+        }
+    }
+
+    public function isBefore(?\DateTimeInterface $dateTime = null): bool
+    {
+        return $this->begin > ($dateTime ?? new \DateTimeImmutable());
+    }
+
+    public function isAfter(?\DateTimeInterface $dateTime = null): bool
+    {
+        return $this->end < ($dateTime ?? new \DateTimeImmutable());
+    }
+
+    public function isOnGoing(?\DateTimeInterface $dateTime = null): bool
+    {
+        return $this->begin <= ($dateTime ?? new \DateTimeImmutable())
+            && $this->end >= ($dateTime ?? new \DateTimeImmutable());
+    }
+
+    public function is(Phase $period, ?\DateTimeInterface $dateTime = null): bool
+    {
+        return match ($period) {
+            Phase::before => $this->isBefore($dateTime),
+            Phase::after => $this->isAfter($dateTime),
+            Phase::onGoing => $this->isOnGoing($dateTime)
+        };
+    }
+
+    public function getPhase(?\DateTimeInterface $dateTime = null): Phase
+    {
+        if ($this->isBefore($dateTime)) {
+            return Phase::before;
+        }
+        if ($this->isAfter($dateTime)) {
+            return Phase::after;
+        }
+        if ($this->isOnGoing($dateTime)) {
+            return Phase::onGoing;
+        }
+        throw new \LogicException();
+    }
+
+    public function duration(): \DateInterval
+    {
+        return $this->end->diff($this->begin);
+    }
+}
diff --git a/src/DateTime/Phase.php b/src/DateTime/Phase.php
new file mode 100644
index 0000000..c6d43ab
--- /dev/null
+++ b/src/DateTime/Phase.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Fykosak\Utils\DateTime;
+
+enum Phase
+{
+    case before;
+    case after;
+    case onGoing;
+}
diff --git a/src/Localization/GettextTranslator.php b/src/Localization/GettextTranslator.php
index b162f81..5ec8361 100644
--- a/src/Localization/GettextTranslator.php
+++ b/src/Localization/GettextTranslator.php
@@ -60,7 +60,7 @@ public function getSupportedLanguages(): array
      * @phpstan-param array<TLang,TValue>|LangMap<TLang,TValue> $map
      * @phpstan-return TValue
      */
-    public function getVariant($map)
+    public function getVariant($map): mixed
     {
         if ($map instanceof LangMap) {
             return $map->get($this->lang);
diff --git a/src/Localization/LangMap.php b/src/Localization/LangMap.php
index c078507..8a3d4bc 100644
--- a/src/Localization/LangMap.php
+++ b/src/Localization/LangMap.php
@@ -27,7 +27,7 @@ public function __construct(array $variants)
      * @phpstan-param TLang $lang
      * @phpstan-return TValue
      */
-    public function __get(string $lang)
+    public function __get(string $lang): mixed
     {
         return $this->get($lang);
     }
@@ -36,7 +36,7 @@ public function __get(string $lang)
      * @phpstan-param TLang $lang
      * @phpstan-return TValue
      */
-    public function get(string $lang)
+    public function get(string $lang): mixed
     {
         return $this->variants[$lang] ?? null;
     }
diff --git a/src/Logging/Message.php b/src/Logging/Message.php
index 1816464..5b06f36 100644
--- a/src/Logging/Message.php
+++ b/src/Logging/Message.php
@@ -4,29 +4,14 @@
 
 namespace Fykosak\Utils\Logging;
 
-use Nette\SmartObject;
 use Nette\Utils\Html;
 
 class Message
 {
-    use SmartObject;
-
-    public const LVL_ERROR = 'danger';
-    public const LVL_WARNING = 'warning';
-    public const LVL_SUCCESS = 'success';
-    public const LVL_INFO = 'info';
-    public const LVL_PRIMARY = 'primary';
-
-    public $text;
-    public string $level;
-
-    /**
-     * @param string|Html $message
-     */
-    public function __construct($message, string $level)
-    {
-        $this->text = $message;
-        $this->level = $level;
+    public function __construct(
+        public readonly string|Html $text,
+        public readonly MessageLevel $level
+    ) {
     }
 
     /**
@@ -36,7 +21,7 @@ public function __toArray(): array
     {
         return [
             'text' => ($this->text instanceof Html) ? $this->text->toHtml() : $this->text,
-            'level' => $this->level,
+            'level' => $this->level->value,
         ];
     }
 }
diff --git a/src/Logging/MessageLevel.php b/src/Logging/MessageLevel.php
new file mode 100644
index 0000000..c5dacd7
--- /dev/null
+++ b/src/Logging/MessageLevel.php
@@ -0,0 +1,14 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Fykosak\Utils\Logging;
+
+enum MessageLevel: string
+{
+    case Error = 'danger';
+    case Warning = 'warning';
+    case Success = 'success';
+    case Info = 'info';
+    case Primary = 'primary';
+}
diff --git a/src/Price/Currency.php b/src/Price/Currency.php
index 65e3cbe..c6df72d 100644
--- a/src/Price/Currency.php
+++ b/src/Price/Currency.php
@@ -4,67 +4,20 @@
 
 namespace Fykosak\Utils\Price;
 
-use Nette\NotImplementedException;
-use Nette\SmartObject;
-
 /**
  * something like enum :)
  */
-final class Currency
+enum Currency: string
 {
-    use SmartObject;
-
-    public const EUR = 'EUR';
-    public const CZK = 'CZK';
-
-    public string $value;
-
-    /**
-     * @throws NotImplementedException
-     */
-    public function __construct(string $currency)
-    {
-        $currency = strtoupper($currency);
-        if (!in_array($currency, [self::EUR, self::CZK])) {
-            throw new NotImplementedException(sprintf(_('Currency "%s" is not supported'), $currency));
-        }
-        $this->value = $currency;
-    }
-
-    /**
-     * @return self[]
-     */
-    public static function cases(): array
-    {
-        return [new self(self::CZK), new self(self::EUR)];
-    }
-
-    public static function tryFrom(string $currency): ?self
-    {
-        try {
-            return new self($currency);
-        } catch (NotImplementedException $exception) {
-            return null;
-        }
-    }
-
-    /**
-     * @throws NotImplementedException
-     */
-    public static function from(string $currency): self
-    {
-        return new self($currency);
-    }
+    case EUR = 'EUR';
+    case CZK = 'CZK';
 
     public function getLabel(): string
     {
-        switch ($this->value) {
-            case self::EUR:
-                return '€';
-            case self::CZK:
-                return 'Kč';
-        }
-        return '';
+        return match ($this) {
+            self::EUR => '€',
+            self::CZK => 'Kč',
+        };
     }
 
     public function format(float $amount): string
diff --git a/src/Price/MultiCurrencyPrice.php b/src/Price/MultiCurrencyPrice.php
index 22e25b5..d642d8f 100644
--- a/src/Price/MultiCurrencyPrice.php
+++ b/src/Price/MultiCurrencyPrice.php
@@ -76,7 +76,7 @@ public function add(self $multiPrice): void
 
     public function __get(string $name): ?Price
     {
-        return $this->getPrice(Currency::from($name));
+        return $this->getPrice(Currency::from(strtoupper($name)));
     }
 
     public function __set(string $name, Price $value): void
diff --git a/src/Price/Price.php b/src/Price/Price.php
index 64fae1b..354ae1e 100644
--- a/src/Price/Price.php
+++ b/src/Price/Price.php
@@ -4,22 +4,15 @@
 
 namespace Fykosak\Utils\Price;
 
-use Nette\SmartObject;
-
-/**
- * @phpstan-type TSerializedPrice array{currency:string,amount:float}
- */
 final class Price
 {
-    use SmartObject;
-
-    private Currency $currency;
     private float $amount;
 
-    public function __construct(Currency $currency, ?float $amount = null)
-    {
+    public function __construct(
+        private readonly Currency $currency,
+        ?float $amount = null
+    ) {
         $this->amount = $amount ?? 0;
-        $this->currency = $currency;
     }
 
     /**
@@ -27,7 +20,7 @@ public function __construct(Currency $currency, ?float $amount = null)
      */
     public function add(Price $price): void
     {
-        if ($this->currency->value !== $price->getCurrency()->value) {
+        if ($this->currency !== $price->getCurrency()) {
             throw new \LogicException('Currencies are not a same');
         }
         $this->amount += $price->getAmount();
@@ -54,7 +47,7 @@ public function __toString(): string
     }
 
     /**
-     * @phpstan-return TSerializedPrice
+     * @phpstan-return array{currency:string,amount:float}
      */
     public function __serialize(): array
     {
diff --git a/src/UI/Navigation/NavItem.php b/src/UI/Navigation/NavItem.php
index 3683fef..b873300 100644
--- a/src/UI/Navigation/NavItem.php
+++ b/src/UI/Navigation/NavItem.php
@@ -5,35 +5,19 @@
 namespace Fykosak\Utils\UI\Navigation;
 
 use Fykosak\Utils\UI\Title;
-use Nette\SmartObject;
 
 class NavItem
 {
-    use SmartObject;
-
-    public string $destination;
-    /** @phpstan-var array<string,scalar> */
-    public array $linkParams;
-    public Title $title;
-    /** @var NavItem[] */
-    public array $children;
-    public bool $active;
-
     /**
      * @phpstan-param array<string,scalar> $linkParams
      * @phpstan-param NavItem[] $children
      */
     public function __construct(
-        Title $title,
-        string $destination = '#',
-        array $linkParams = [],
-        array $children = [],
-        bool $active = false
+        public readonly Title $title,
+        public readonly string $destination = '#',
+        public readonly array $linkParams = [],
+        public readonly array $children = [],
+        public readonly bool $active = false
     ) {
-        $this->active = $active;
-        $this->destination = $destination;
-        $this->linkParams = $linkParams;
-        $this->title = $title;
-        $this->children = $children;
     }
 }
diff --git a/src/UI/PageTitle.php b/src/UI/PageTitle.php
index 983dc7b..eb451e4 100644
--- a/src/UI/PageTitle.php
+++ b/src/UI/PageTitle.php
@@ -8,17 +8,13 @@
 
 class PageTitle extends Title
 {
-    /** @var string|Html|null */
-    public $subTitle;
-
-    /**
-     * @param string|Html $title
-     * @param string|Html|null $subTitle
-     */
-    public function __construct(?string $id, $title, ?string $icon = null, $subTitle = null)
-    {
+    public function __construct(
+        ?string $id,
+        string|Html $title,
+        ?string $icon = null,
+        public string|Html|null $subTitle = null
+    ) {
         parent::__construct($id, $title, $icon);
-        $this->subTitle = $subTitle;
     }
 
     public function toHtml(bool $includeSubTitle = false): Html
diff --git a/src/UI/Title.php b/src/UI/Title.php
index b5fbeb8..5cbaf7b 100644
--- a/src/UI/Title.php
+++ b/src/UI/Title.php
@@ -9,18 +9,13 @@
 
 class Title
 {
-    /** @var string|Html */
-    public $title;
-    public ?string $icon;
-    public string $id;
+    public readonly string $id;
 
-    /**
-     * @param string|Html $title
-     */
-    public function __construct(?string $id, $title, ?string $icon = null)
-    {
-        $this->title = $title;
-        $this->icon = $icon;
+    public function __construct(
+        ?string $id,
+        public readonly string|Html $title,
+        public readonly ?string $icon = null
+    ) {
         $this->id = $id ?? Random::generate(10, 'a-z');
     }
 
diff --git a/tests/Tests/Price/TestCurrency.phpt b/tests/Tests/Price/TestCurrency.phpt
index 3dfd0a6..5487c1f 100644
--- a/tests/Tests/Price/TestCurrency.phpt
+++ b/tests/Tests/Price/TestCurrency.phpt
@@ -13,11 +13,6 @@ require_once __DIR__ . '/../FakeBootstrap.php';
 
 class TestCurrency extends BaseTest
 {
-    public function testCreateNonExist(): void
-    {
-        Assert::exception(fn() => new Currency('XBT'), \Exception::class);
-    }
-
     public function testCases(): void
     {
         foreach (Currency::cases() as $case) {
@@ -27,21 +22,21 @@ class TestCurrency extends BaseTest
 
     public function testFromExists(): void
     {
-        $currency = Currency::from(Currency::CZK);
+        $currency = Currency::CZK;
         Assert::type(Currency::class, $currency);
-        $currencyLower = Currency::from('czk');
+        $currencyLower = Currency::from('CZK');
         Assert::type(Currency::class, $currencyLower);
     }
 
     public function testTryFromExists(): void
     {
-        $currency = Currency::tryFrom(Currency::CZK);
+        $currency = Currency::CZK;
         Assert::type(Currency::class, $currency);
     }
 
     public function testFromNonExists(): void
     {
-        Assert::exception(fn() => Currency::from('XBT'), \Exception::class);
+        Assert::exception(fn() => Currency::from('XBT'), \ValueError::class);
     }
 
     public function testTryFromNonExists(): void
@@ -52,7 +47,7 @@ class TestCurrency extends BaseTest
 
     public function testRender(): void
     {
-        $currency = new Currency(Currency::CZK);
+        $currency = Currency::CZK;
         Assert::same('2.00 Kč', $currency->format(2.0));
     }
 }
diff --git a/tests/Tests/Price/TestMultiPrice.phpt b/tests/Tests/Price/TestMultiPrice.phpt
index 48bb789..e6ed837 100644
--- a/tests/Tests/Price/TestMultiPrice.phpt
+++ b/tests/Tests/Price/TestMultiPrice.phpt
@@ -24,14 +24,14 @@ class TestMultiPrice extends BaseTest
 
     public function testCreateFilled(): void
     {
-        $multiPrice = new MultiCurrencyPrice([new Price(Currency::from(Currency::CZK))]);
+        $multiPrice = new MultiCurrencyPrice([new Price(Currency::CZK)]);
         $price = $multiPrice->czk;
         Assert::type(Price::class, $price);
     }
 
     public function testGetAccess(): void
     {
-        $multiPrice = new MultiCurrencyPrice([new Price(Currency::from(Currency::CZK), 4),]);
+        $multiPrice = new MultiCurrencyPrice([new Price(Currency::CZK, 4),]);
         Assert::type(Price::class, $multiPrice->czk);
         Assert::exception(fn() => $multiPrice->eur, \OutOfRangeException::class);
         Assert::type(Price::class, $multiPrice->CZK);
@@ -39,32 +39,32 @@ class TestMultiPrice extends BaseTest
 
     public function testSetAccess(): void
     {
-        $multiPrice = new MultiCurrencyPrice([new Price(Currency::from(Currency::CZK), 4),]);
-        $multiPrice->czk = new Price(Currency::from(Currency::CZK), 2);
+        $multiPrice = new MultiCurrencyPrice([new Price(Currency::CZK, 4),]);
+        $multiPrice->czk = new Price(Currency::CZK, 2);
         Assert::type(Price::class, $multiPrice->czk);
         Assert::same(2.0, $multiPrice->czk->getAmount());
 
         Assert::exception(
-            fn() => $multiPrice->czk = new Price(Currency::from(Currency::EUR)),
+            fn() => $multiPrice->czk = new Price(Currency::EUR),
             \LogicException::class
         );
         Assert::exception(
-            fn() => $multiPrice->CZK = new Price(Currency::from(Currency::EUR)),
+            fn() => $multiPrice->CZK = new Price(Currency::EUR),
             \LogicException::class
         );
         Assert::exception(
-            fn() => $multiPrice->eur = new Price(Currency::from(Currency::EUR)),
+            fn() => $multiPrice->eur = new Price(Currency::EUR),
             \OutOfRangeException::class
         );
     }
 
     public function testCreateSum(): void
     {
-        $multiPrice1 = new MultiCurrencyPrice([new Price(Currency::from(Currency::CZK), 2)]);
+        $multiPrice1 = new MultiCurrencyPrice([new Price(Currency::CZK, 2)]);
         $multiPrice2 = new MultiCurrencyPrice(
             [
-                new Price(Currency::from(Currency::CZK), 1),
-                new Price(Currency::from(Currency::EUR), 4),
+                new Price(Currency::CZK, 1),
+                new Price(Currency::EUR, 4),
             ]
         );
 
diff --git a/tests/Tests/Price/TestPrice.phpt b/tests/Tests/Price/TestPrice.phpt
index e73e58c..c4ad895 100644
--- a/tests/Tests/Price/TestPrice.phpt
+++ b/tests/Tests/Price/TestPrice.phpt
@@ -16,8 +16,8 @@ class TestPrice extends BaseTest
 {
     public function testAddSame(): void
     {
-        $price1 = new Price(new Currency(Currency::CZK), 2);
-        $price2 = new Price(new Currency(Currency::CZK), 4);
+        $price1 = new Price(Currency::CZK, 2);
+        $price2 = new Price(Currency::CZK, 4);
         $price1->add($price2);
         Assert::same(6.0, $price1->getAmount());
         Assert::same(4.0, $price2->getAmount());
@@ -25,14 +25,14 @@ class TestPrice extends BaseTest
 
     public function testNotSame(): void
     {
-        $price1 = new Price(new Currency(Currency::CZK), 2);
-        $price2 = new Price(new Currency(Currency::EUR), 4);
+        $price1 = new Price(Currency::CZK, 2);
+        $price2 = new Price(Currency::EUR, 4);
         Assert::exception(fn() => $price1->add($price2), \LogicException::class);
     }
 
     public function testAdd(): void
     {
-        $price1 = new Price(new Currency(Currency::CZK), 2);
+        $price1 = new Price(Currency::CZK, 2);
         $price1->addAmount(3.5);
         Assert::same(5.5, $price1->getAmount());
     }