diff --git a/wp-admin/includes/ajax-actions.php b/wp-admin/includes/ajax-actions.php
index c565817914..f273c4df6f 100644
--- a/wp-admin/includes/ajax-actions.php
+++ b/wp-admin/includes/ajax-actions.php
@@ -1464,7 +1464,7 @@ function wp_ajax_add_meta() {
 			$post_data['post_ID']     = $pid;
 			$post_data['post_type']   = $post->post_type;
 			$post_data['post_status'] = 'draft';
-			$now                      = current_time( 'timestamp', 1 );
+			$now                      = time();
 			/* translators: 1: Post creation date, 2: Post creation time */
 			$post_data['post_title'] = sprintf( __( 'Draft created on %1$s at %2$s' ), date( __( 'F j, Y' ), $now ), date( __( 'g:i a' ), $now ) );
 
diff --git a/wp-admin/includes/dashboard.php b/wp-admin/includes/dashboard.php
index 7bebe3ff20..e3e8cca9a7 100644
--- a/wp-admin/includes/dashboard.php
+++ b/wp-admin/includes/dashboard.php
@@ -858,8 +858,9 @@ function wp_dashboard_recent_posts( $args ) {
 
 		echo '<ul>';
 
-		$today    = date( 'Y-m-d', current_time( 'timestamp' ) );
-		$tomorrow = date( 'Y-m-d', strtotime( '+1 day', current_time( 'timestamp' ) ) );
+		$today    = current_time( 'Y-m-d' );
+		$tomorrow = gmdate( 'Y-m-d', strtotime( '+1 day', current_time( 'timestamp' ) ) );
+		$year     = current_time( 'Y' );
 
 		while ( $posts->have_posts() ) {
 			$posts->the_post();
@@ -869,7 +870,7 @@ function wp_dashboard_recent_posts( $args ) {
 				$relative = __( 'Today' );
 			} elseif ( date( 'Y-m-d', $time ) == $tomorrow ) {
 				$relative = __( 'Tomorrow' );
-			} elseif ( date( 'Y', $time ) !== date( 'Y', current_time( 'timestamp' ) ) ) {
+			} elseif ( date( 'Y', $time ) !== $year ) {
 				/* translators: date and time format for recent posts on the dashboard, from a different calendar year, see https://secure.php.net/date */
 				$relative = date_i18n( __( 'M jS Y' ), $time );
 			} else {
diff --git a/wp-admin/includes/template.php b/wp-admin/includes/template.php
index 6336ee3d2d..a06f9228aa 100644
--- a/wp-admin/includes/template.php
+++ b/wp-admin/includes/template.php
@@ -774,20 +774,19 @@ function touch_time( $edit = 1, $for_post = 1, $tab_index = 0, $multi = 0 ) {
 	// todo: Remove this?
 	// echo '<label for="timestamp" style="display: block;"><input type="checkbox" class="checkbox" name="edit_date" value="1" id="timestamp"'.$tab_index_attribute.' /> '.__( 'Edit timestamp' ).'</label><br />';
 
-	$time_adj  = current_time( 'timestamp' );
 	$post_date = ( $for_post ) ? $post->post_date : get_comment()->comment_date;
-	$jj        = ( $edit ) ? mysql2date( 'd', $post_date, false ) : gmdate( 'd', $time_adj );
-	$mm        = ( $edit ) ? mysql2date( 'm', $post_date, false ) : gmdate( 'm', $time_adj );
-	$aa        = ( $edit ) ? mysql2date( 'Y', $post_date, false ) : gmdate( 'Y', $time_adj );
-	$hh        = ( $edit ) ? mysql2date( 'H', $post_date, false ) : gmdate( 'H', $time_adj );
-	$mn        = ( $edit ) ? mysql2date( 'i', $post_date, false ) : gmdate( 'i', $time_adj );
-	$ss        = ( $edit ) ? mysql2date( 's', $post_date, false ) : gmdate( 's', $time_adj );
+	$jj        = ( $edit ) ? mysql2date( 'd', $post_date, false ) : current_time( 'd' );
+	$mm        = ( $edit ) ? mysql2date( 'm', $post_date, false ) : current_time( 'm' );
+	$aa        = ( $edit ) ? mysql2date( 'Y', $post_date, false ) : current_time( 'Y' );
+	$hh        = ( $edit ) ? mysql2date( 'H', $post_date, false ) : current_time( 'H' );
+	$mn        = ( $edit ) ? mysql2date( 'i', $post_date, false ) : current_time( 'i' );
+	$ss        = ( $edit ) ? mysql2date( 's', $post_date, false ) : current_time( 's' );
 
-	$cur_jj = gmdate( 'd', $time_adj );
-	$cur_mm = gmdate( 'm', $time_adj );
-	$cur_aa = gmdate( 'Y', $time_adj );
-	$cur_hh = gmdate( 'H', $time_adj );
-	$cur_mn = gmdate( 'i', $time_adj );
+	$cur_jj = current_time( 'd' );
+	$cur_mm = current_time( 'm' );
+	$cur_aa = current_time( 'Y' );
+	$cur_hh = current_time( 'H' );
+	$cur_mn = current_time( 'i' );
 
 	$month = '<label><span class="screen-reader-text">' . __( 'Month' ) . '</span><select ' . ( $multi ? '' : 'id="mm" ' ) . 'name="mm"' . $tab_index_attribute . ">\n";
 	for ( $i = 1; $i < 13; $i = $i + 1 ) {
diff --git a/wp-admin/includes/user.php b/wp-admin/includes/user.php
index 56224cfb65..356a7c68fc 100644
--- a/wp-admin/includes/user.php
+++ b/wp-admin/includes/user.php
@@ -1392,7 +1392,7 @@ abstract class WP_Privacy_Requests_Table extends WP_List_Table {
 			return '';
 		}
 
-		$time_diff = current_time( 'timestamp', true ) - $timestamp;
+		$time_diff = time() - $timestamp;
 
 		if ( $time_diff >= 0 && $time_diff < DAY_IN_SECONDS ) {
 			/* translators: human readable timestamp */
diff --git a/wp-includes/blocks/calendar.php b/wp-includes/blocks/calendar.php
new file mode 100644
index 0000000000..9177997692
--- /dev/null
+++ b/wp-includes/blocks/calendar.php
@@ -0,0 +1,71 @@
+<?php
+/**
+ * Server-side rendering of the `core/calendar` block.
+ *
+ * @package WordPress
+ */
+
+/**
+ * Renders the `core/calendar` block on server.
+ *
+ * @param array $attributes The block attributes.
+ *
+ * @return string Returns the block content.
+ */
+function render_block_core_calendar( $attributes ) {
+	global $monthnum, $year, $post;
+	$previous_monthnum = $monthnum;
+	$previous_year     = $year;
+
+	if ( isset( $attributes['month'] ) ) {
+		// phpcs:ignore WordPress.WP.GlobalVariablesOverride.OverrideProhibited
+		$monthnum = $attributes['month'];
+	}
+
+	if ( isset( $attributes['year'] ) ) {
+		// phpcs:ignore WordPress.WP.GlobalVariablesOverride.OverrideProhibited
+		$year = $attributes['year'];
+	}
+
+	$custom_class_name = empty( $attributes['className'] ) ? '' : ' ' . $attributes['className'];
+	$align_class_name  = empty( $attributes['align'] ) ? '' : ' ' . "align{$attributes['align']}";
+
+	return sprintf(
+		'<div class="%1$s">%2$s</div>',
+		esc_attr( 'wp-block-calendar' . $custom_class_name . $align_class_name ),
+		get_calendar( true, false )
+	);
+
+	// phpcs:ignore WordPress.WP.GlobalVariablesOverride.OverrideProhibited
+	$monthnum = $previous_monthnum;
+	// phpcs:ignore WordPress.WP.GlobalVariablesOverride.OverrideProhibited
+	$year = $previous_year;
+}
+
+/**
+ * Registers the `core/calendar` block on server.
+ */
+function register_block_core_calendar() {
+	register_block_type(
+		'core/calendar',
+		array(
+			'attributes'      => array(
+				'align'     => array(
+					'type' => 'string',
+				),
+				'className' => array(
+					'type' => 'string',
+				),
+				'month'     => array(
+					'type' => 'integer',
+				),
+				'year'      => array(
+					'type' => 'integer',
+				),
+			),
+			'render_callback' => 'render_block_core_calendar',
+		)
+	);
+}
+
+add_action( 'init', 'register_block_core_calendar' );
diff --git a/wp-includes/blocks/rss.php b/wp-includes/blocks/rss.php
new file mode 100644
index 0000000000..b5fe3abaf5
--- /dev/null
+++ b/wp-includes/blocks/rss.php
@@ -0,0 +1,137 @@
+<?php
+/**
+ * Server-side rendering of the `core/rss` block.
+ *
+ * @package WordPress
+ */
+
+/**
+ * Renders the `core/rss` block on server.
+ *
+ * @param array $attributes The block attributes.
+ *
+ * @return string Returns the block content with received rss items.
+ */
+function render_block_core_rss( $attributes ) {
+	$rss = fetch_feed( $attributes['feedURL'] );
+
+	if ( is_wp_error( $rss ) ) {
+		return '<div class="components-placeholder"><div class="notice notice-error"><strong>' . __( 'RSS Error:' ) . '</strong> ' . $rss->get_error_message() . '</div></div>';
+	}
+
+	if ( ! $rss->get_item_quantity() ) {
+		// PHP 5.2 compatibility. See: http://simplepie.org/wiki/faq/i_m_getting_memory_leaks.
+		$rss->__destruct();
+		unset( $rss );
+
+		return '<div class="components-placeholder"><div class="notice notice-error">' . __( 'An error has occurred, which probably means the feed is down. Try again later.' ) . '</div></div>';
+	}
+
+	$rss_items  = $rss->get_items( 0, $attributes['itemsToShow'] );
+	$list_items = '';
+	foreach ( $rss_items as $item ) {
+		$title = esc_html( trim( strip_tags( $item->get_title() ) ) );
+		if ( empty( $title ) ) {
+			$title = __( '(Untitled)' );
+		}
+		$link = $item->get_link();
+		$link = esc_url( $link );
+		if ( $link ) {
+			$title = "<a href='{$link}'>{$title}</a>";
+		}
+		$title = "<div class='wp-block-rss__item-title'>{$title}</div>";
+
+		$date = '';
+		if ( $attributes['displayDate'] ) {
+			$date = $item->get_date( 'U' );
+
+			if ( $date ) {
+				$date = sprintf(
+					'<time datetime="%1$s" class="wp-block-rss__item-publish-date">%2$s</time> ',
+					date_i18n( get_option( 'c' ), $date ),
+					date_i18n( get_option( 'date_format' ), $date )
+				);
+			}
+		}
+
+		$author = '';
+		if ( $attributes['displayAuthor'] ) {
+			$author = $item->get_author();
+			if ( is_object( $author ) ) {
+				$author = $author->get_name();
+				$author = '<span class="wp-block-rss__item-author">' . __( 'by' ) . ' ' . esc_html( strip_tags( $author ) ) . '</span>';
+			}
+		}
+
+		$excerpt = '';
+		if ( $attributes['displayExcerpt'] ) {
+			$excerpt = html_entity_decode( $item->get_description(), ENT_QUOTES, get_option( 'blog_charset' ) );
+			$excerpt = esc_attr( wp_trim_words( $excerpt, $attributes['excerptLength'], ' [&hellip;]' ) );
+
+			// Change existing [...] to [&hellip;].
+			if ( '[...]' == substr( $excerpt, -5 ) ) {
+				$excerpt = substr( $excerpt, 0, -5 ) . '[&hellip;]';
+			}
+
+			$excerpt = '<div class="wp-block-rss__item-excerpt">' . esc_html( $excerpt ) . '</div>';
+		}
+
+		$list_items .= "<li class='wp-block-rss__item'>{$title}{$date}{$author}{$excerpt}</li>";
+	}
+
+	$classes           = 'grid' === $attributes['blockLayout'] ? ' is-grid columns-' . $attributes['columns'] : '';
+	$list_items_markup = "<ul class='wp-block-rss{$classes}'>{$list_items}</ul>";
+
+	// PHP 5.2 compatibility. See: http://simplepie.org/wiki/faq/i_m_getting_memory_leaks.
+	$rss->__destruct();
+	unset( $rss );
+
+	return $list_items_markup;
+}
+
+/**
+ * Registers the `core/rss` block on server.
+ */
+function register_block_core_rss() {
+	register_block_type( 'core/rss',
+		array(
+			'attributes'      => array(
+				'columns'        => array(
+					'type'    => 'number',
+					'default' => 2,
+				),
+				'blockLayout'    => array(
+					'type'    => 'string',
+					'default' => 'list',
+				),
+				'feedURL'        => array(
+					'type'    => 'string',
+					'default' => '',
+				),
+				'itemsToShow'    => array(
+					'type'    => 'number',
+					'default' => 5,
+				),
+				'displayExcerpt' => array(
+					'type'    => 'boolean',
+					'default' => false,
+				),
+				'displayAuthor'  => array(
+					'type'    => 'boolean',
+					'default' => false,
+				),
+				'displayDate'    => array(
+					'type'    => 'boolean',
+					'default' => false,
+				),
+				'excerptLength'  => array(
+					'type'    => 'number',
+					'default' => 55,
+				),
+			),
+			'render_callback' => 'render_block_core_rss',
+		)
+	);
+}
+
+add_action( 'init', 'register_block_core_rss' );
diff --git a/wp-includes/blocks/search.php b/wp-includes/blocks/search.php
new file mode 100644
index 0000000000..ac7da463e9
--- /dev/null
+++ b/wp-includes/blocks/search.php
@@ -0,0 +1,82 @@
+<?php
+/**
+ * Server-side rendering of the `core/search` block.
+ *
+ * @package WordPress
+ */
+
+/**
+ * Dynamically renders the `core/search` block.
+ *
+ * @param array $attributes The block attributes.
+ *
+ * @return string The search block markup.
+ */
+function render_block_core_search( $attributes ) {
+	static $instance_id = 0;
+
+	$input_id = 'wp-block-search__input-' . ++$instance_id;
+
+	if ( ! empty( $attributes['label'] ) ) {
+		$label_markup = sprintf(
+			'<label for="%s" class="wp-block-search__label">%s</label>',
+			$input_id,
+			$attributes['label']
+		);
+	}
+
+	$input_markup = sprintf(
+		'<input type="search" id="%s" class="wp-block-search__input" name="s" value="%s" placeholder="%s" />',
+		$input_id,
+		esc_attr( get_search_query() ),
+		esc_attr( $attributes['placeholder'] )
+	);
+
+	if ( ! empty( $attributes['buttonText'] ) ) {
+		$button_markup = sprintf(
+			'<button type="submit" class="wp-block-search__button">%s</button>',
+			$attributes['buttonText']
+		);
+	}
+
+	$class = 'wp-block-search';
+	if ( isset( $attributes['className'] ) ) {
+		$class .= ' ' . $attributes['className'];
+	}
+
+	return sprintf(
+		'<form class="%s" role="search" method="get" action="%s">%s</form>',
+		$class,
+		esc_url( home_url( '/' ) ),
+		$label_markup . $input_markup . $button_markup
+	);
+}
+
+/**
+ * Registers the `core/search` block on the server.
+ */
+function register_block_core_search() {
+	register_block_type(
+		'core/search',
+		array(
+			'attributes'      => array(
+				'label'       => array(
+					'type'    => 'string',
+					'default' => __( 'Search' ),
+				),
+				'placeholder' => array(
+					'type'    => 'string',
+					'default' => '',
+				),
+				'buttonText'  => array(
+					'type'    => 'string',
+					'default' => __( 'Search' ),
+				),
+			),
+
+			'render_callback' => 'render_block_core_search',
+		)
+	);
+}
+
+add_action( 'init', 'register_block_core_search' );
diff --git a/wp-includes/blocks/tag-cloud.php b/wp-includes/blocks/tag-cloud.php
new file mode 100644
index 0000000000..c60f8a1dd6
--- /dev/null
+++ b/wp-includes/blocks/tag-cloud.php
@@ -0,0 +1,71 @@
+<?php
+/**
+ * Server-side rendering of the `core/tag-cloud` block.
+ *
+ * @package WordPress
+ */
+
+/**
+ * Renders the `core/tag-cloud` block on server.
+ *
+ * @param array $attributes The block attributes.
+ *
+ * @return string Returns the tag cloud for selected taxonomy.
+ */
+function render_block_core_tag_cloud( $attributes ) {
+	$class = isset( $attributes['align'] ) ?
+		"wp-block-tag-cloud align{$attributes['align']}" :
+		'wp-block-tag-cloud';
+
+	if ( isset( $attributes['className'] ) ) {
+		$class .= ' ' . $attributes['className'];
+	}
+
+	$args = array(
+		'echo'       => false,
+		'taxonomy'   => $attributes['taxonomy'],
+		'show_count' => $attributes['showTagCounts'],
+	);
+
+	$tag_cloud = wp_tag_cloud( $args );
+
+	if ( ! $tag_cloud ) {
+		$tag_cloud = esc_html( __( 'No terms to show.' ) );
+	}
+
+	return sprintf(
+		'<p class="%1$s">%2$s</p>',
+		esc_attr( $class ),
+		$tag_cloud
+	);
+}
+
+/**
+ * Registers the `core/tag-cloud` block on server.
+ */
+function register_block_core_tag_cloud() {
+	register_block_type(
+		'core/tag-cloud',
+		array(
+			'attributes'      => array(
+				'taxonomy'      => array(
+					'type'    => 'string',
+					'default' => 'post_tag',
+				),
+				'className'     => array(
+					'type' => 'string',
+				),
+				'showTagCounts' => array(
+					'type'    => 'boolean',
+					'default' => false,
+				),
+				'align'         => array(
+					'type' => 'string',
+				),
+			),
+			'render_callback' => 'render_block_core_tag_cloud',
+		)
+	);
+}
+
+add_action( 'init', 'register_block_core_tag_cloud' );
diff --git a/wp-includes/general-template.php b/wp-includes/general-template.php
index 11d4b77ff4..f63bafb406 100644
--- a/wp-includes/general-template.php
+++ b/wp-includes/general-template.php
@@ -2005,7 +2005,6 @@ function get_calendar( $initial = true, $echo = true ) {
 	}
 	// week_begins = 0 stands for Sunday
 	$week_begins = (int) get_option( 'start_of_week' );
-	$ts          = current_time( 'timestamp' );
 
 	// Let's figure out when we are
 	if ( ! empty( $monthnum ) && ! empty( $year ) ) {
@@ -2025,8 +2024,8 @@ function get_calendar( $initial = true, $echo = true ) {
 			$thismonth = zeroise( (int) substr( $m, 4, 2 ), 2 );
 		}
 	} else {
-		$thisyear  = gmdate( 'Y', $ts );
-		$thismonth = gmdate( 'm', $ts );
+		$thisyear  = current_time( 'Y' );
+		$thismonth = current_time( 'm' );
 	}
 
 	$unixmonth = mktime( 0, 0, 0, $thismonth, 1, $thisyear );
@@ -2136,9 +2135,9 @@ function get_calendar( $initial = true, $echo = true ) {
 		}
 		$newrow = false;
 
-		if ( $day == gmdate( 'j', $ts ) &&
-			$thismonth == gmdate( 'm', $ts ) &&
-			$thisyear == gmdate( 'Y', $ts ) ) {
+		if ( $day == current_time( 'j' ) &&
+			$thismonth == current_time( 'm' ) &&
+			$thisyear == current_time( 'Y' ) ) {
 			$calendar_output .= '<td id="today">';
 		} else {
 			$calendar_output .= '<td>';
diff --git a/wp-includes/link-template.php b/wp-includes/link-template.php
index be39e36279..ef604dcc7d 100644
--- a/wp-includes/link-template.php
+++ b/wp-includes/link-template.php
@@ -470,7 +470,7 @@ function get_attachment_link( $post = null, $leavename = false ) {
 function get_year_link( $year ) {
 	global $wp_rewrite;
 	if ( ! $year ) {
-		$year = gmdate( 'Y', current_time( 'timestamp' ) );
+		$year = current_time( 'Y' );
 	}
 	$yearlink = $wp_rewrite->get_year_permastruct();
 	if ( ! empty( $yearlink ) ) {
@@ -505,10 +505,10 @@ function get_year_link( $year ) {
 function get_month_link( $year, $month ) {
 	global $wp_rewrite;
 	if ( ! $year ) {
-		$year = gmdate( 'Y', current_time( 'timestamp' ) );
+		$year = current_time( 'Y' );
 	}
 	if ( ! $month ) {
-		$month = gmdate( 'm', current_time( 'timestamp' ) );
+		$month = current_time( 'm' );
 	}
 	$monthlink = $wp_rewrite->get_month_permastruct();
 	if ( ! empty( $monthlink ) ) {
@@ -546,13 +546,13 @@ function get_month_link( $year, $month ) {
 function get_day_link( $year, $month, $day ) {
 	global $wp_rewrite;
 	if ( ! $year ) {
-		$year = gmdate( 'Y', current_time( 'timestamp' ) );
+		$year = current_time( 'Y' );
 	}
 	if ( ! $month ) {
-		$month = gmdate( 'm', current_time( 'timestamp' ) );
+		$month = current_time( 'm' );
 	}
 	if ( ! $day ) {
-		$day = gmdate( 'j', current_time( 'timestamp' ) );
+		$day = current_time( 'j' );
 	}
 
 	$daylink = $wp_rewrite->get_day_permastruct();
diff --git a/wp-includes/ms-functions.php b/wp-includes/ms-functions.php
index 620e9c9194..75dab9e09c 100644
--- a/wp-includes/ms-functions.php
+++ b/wp-includes/ms-functions.php
@@ -518,7 +518,7 @@ function wpmu_validate_user_signup( $user_name, $user_email ) {
 	$signup = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $wpdb->signups WHERE user_login = %s", $user_name ) );
 	if ( $signup != null ) {
 		$registered_at = mysql2date( 'U', $signup->registered );
-		$now           = current_time( 'timestamp', true );
+		$now           = time();
 		$diff          = $now - $registered_at;
 		// If registered more than two days ago, cancel registration and let this signup go through.
 		if ( $diff > 2 * DAY_IN_SECONDS ) {
@@ -530,7 +530,7 @@ function wpmu_validate_user_signup( $user_name, $user_email ) {
 
 	$signup = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $wpdb->signups WHERE user_email = %s", $user_email ) );
 	if ( $signup != null ) {
-		$diff = current_time( 'timestamp', true ) - mysql2date( 'U', $signup->registered );
+		$diff = time() - mysql2date( 'U', $signup->registered );
 		// If registered more than two days ago, cancel registration and let this signup go through.
 		if ( $diff > 2 * DAY_IN_SECONDS ) {
 			$wpdb->delete( $wpdb->signups, array( 'user_email' => $user_email ) );
@@ -688,7 +688,7 @@ function wpmu_validate_blog_signup( $blogname, $blog_title, $user = '' ) {
 	// Has someone already signed up for this domain?
 	$signup = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $wpdb->signups WHERE domain = %s AND path = %s", $mydomain, $path ) ); // TODO: Check email too?
 	if ( ! empty( $signup ) ) {
-		$diff = current_time( 'timestamp', true ) - mysql2date( 'U', $signup->registered );
+		$diff = time() - mysql2date( 'U', $signup->registered );
 		// If registered more than two days ago, cancel registration and let this signup go through.
 		if ( $diff > 2 * DAY_IN_SECONDS ) {
 			$wpdb->delete(
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 54e23561d4..c1043d473b 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.2-alpha-44808';
+$wp_version = '5.2-alpha-44809';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.