diff --git a/src/Entity/Activity.php b/src/Entity/Activity.php
index 3d622ae..55b46b8 100644
--- a/src/Entity/Activity.php
+++ b/src/Entity/Activity.php
@@ -7,7 +7,7 @@
 
 namespace JuniWalk\Calendar\Entity;
 
-use DateTimeInterface;
+use DateTime;
 use JuniWalk\Calendar\Enums\Day;
 use JuniWalk\Calendar\Event;
 use JuniWalk\Calendar\EventDetail;
@@ -28,8 +28,8 @@ class Activity implements Event, EventDetail, EventLinkable, EventRecurring
 	public mixed $groupId;
 	public string $source;
 	public bool $allDay;
-	public DateTimeInterface $start;
-	public ?DateTimeInterface $end;
+	public DateTime $start;
+	public ?DateTime $end;
 	public string $title;
 	public Html $titleHtml;
 	/** @var string[] */
@@ -47,8 +47,8 @@ class Activity implements Event, EventDetail, EventLinkable, EventRecurring
 	// EventRecurring
 	/** @var DayNumber[] */
 	public array $daysOfWeek;
-	public ?DateTimeInterface $startRecur;
-	public ?DateTimeInterface $endRecur;
+	public ?DateTime $startRecur;
+	public ?DateTime $endRecur;
 	public string $startTime;
 	public string $endTime;
 
@@ -87,21 +87,21 @@ public function getSource(): string
 	}
 
 
-	public function setStart(DateTimeInterface $start): void
+	public function setStart(DateTime $start): void
 	{
 		$this->start = clone $start;
 	}
 
 
-	public function getStart(): DateTimeInterface
+	public function getStart(): DateTime
 	{
 		return $this->start;
 	}
 
 
-	public function setEnd(?DateTimeInterface $end): void
+	public function setEnd(?DateTime $end): void
 	{
-		if ($end instanceof DateTimeInterface) {
+		if ($end instanceof DateTime) {
 			$end = clone $end;
 		}
 
@@ -109,7 +109,7 @@ public function setEnd(?DateTimeInterface $end): void
 	}
 
 
-	public function getEnd(): ?DateTimeInterface
+	public function getEnd(): ?DateTime
 	{
 		return $this->end ?? null;
 	}
@@ -163,7 +163,7 @@ public function setParams(array $params): void
 				continue;
 			}
 
-			if ($value instanceof DateTimeInterface) {
+			if ($value instanceof DateTime) {
 				$value = clone $value;
 			}
 
diff --git a/src/Entity/Options.php b/src/Entity/Options.php
index 8591be5..b9dea4b 100644
--- a/src/Entity/Options.php
+++ b/src/Entity/Options.php
@@ -8,7 +8,6 @@
 namespace JuniWalk\Calendar\Entity;
 
 use DateTime;
-use DateTimeInterface;
 use JuniWalk\Calendar\Calendar;
 use JuniWalk\Calendar\Config;
 use JuniWalk\Calendar\Event;
@@ -392,7 +391,7 @@ public static function createSchema(): Schema
 	}
 
 
-	protected function startsTooSoon(DateTimeInterface $date): bool
+	protected function startsTooSoon(DateTime $date): bool
 	{
 		$dow = (int) $date->format('N');
 
@@ -405,7 +404,7 @@ protected function startsTooSoon(DateTimeInterface $date): bool
 	}
 
 
-	protected function endsTooLate(DateTimeInterface $date): bool
+	protected function endsTooLate(DateTime $date): bool
 	{
 		$dow = (int) $date->format('N');
 
diff --git a/src/Event.php b/src/Event.php
index fbbca29..a91bff8 100644
--- a/src/Event.php
+++ b/src/Event.php
@@ -7,7 +7,7 @@
 
 namespace JuniWalk\Calendar;
 
-use DateTimeInterface as DateTime;
+use DateTime;
 use JsonSerializable;
 
 interface Event extends JsonSerializable
diff --git a/src/Source.php b/src/Source.php
index a6277cf..e55cd70 100644
--- a/src/Source.php
+++ b/src/Source.php
@@ -7,7 +7,7 @@
 
 namespace JuniWalk\Calendar;
 
-use DateTimeInterface as DateTime;
+use DateTime;
 use DateTimeZone;
 use JuniWalk\Calendar\Entity\Legend;
 use Nette\Application\UI\SignalReceiver;
diff --git a/src/SourceEditable.php b/src/SourceEditable.php
index 54b6ade..f351320 100644
--- a/src/SourceEditable.php
+++ b/src/SourceEditable.php
@@ -7,7 +7,7 @@
 
 namespace JuniWalk\Calendar;
 
-use DateTimeInterface as DateTime;
+use DateTime;
 
 interface SourceEditable
 {
diff --git a/src/Sources/CzechHolidaysSource.php b/src/Sources/CzechHolidaysSource.php
index 0a750c7..a1777a0 100644
--- a/src/Sources/CzechHolidaysSource.php
+++ b/src/Sources/CzechHolidaysSource.php
@@ -8,7 +8,6 @@
 namespace JuniWalk\Calendar\Sources;
 
 use DateTime;
-use DateTimeInterface;
 use DateTimeZone;
 use JuniWalk\Calendar\Calendar;
 use JuniWalk\Calendar\Config;
@@ -34,7 +33,7 @@ public function getLegend(): array
 	/**
 	 * @return Event[]
 	 */
-	public function fetchEvents(DateTimeInterface $start, DateTimeInterface $end, DateTimeZone $timeZone): array
+	public function fetchEvents(DateTime $start, DateTime $end, DateTimeZone $timeZone): array
 	{
 		$start = new DateTime($start->format(DateTime::ATOM));
 		$events = [];