diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1e6b612..31e8738 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -38,6 +38,7 @@
 - Fixed error at prev link on first / next link on last entry ([#95](https://github.com/flatpressblog/flatpress/issues/95))
 - Logout redirects to home page again ([#119](https://github.com/flatpressblog/flatpress/issues/119))
 - Fixed disappearing non-Latin characters in page title ([#49](https://github.com/flatpressblog/flatpress/issues/49) and [#91](https://github.com/flatpressblog/flatpress/issues/91))
+- Worked around strftime() marked as deprecated as of PHP 8.1 ([#92](https://github.com/flatpressblog/flatpress/issues/92)) - thx @bohwaz
 
 ## Security
 - Possible XSS prevented: Session cookie missed the "secure" and "httponly" flags
diff --git a/fp-includes/core/core.date.php b/fp-includes/core/core.date.php
index efd2167..acaf595 100755
--- a/fp-includes/core/core.date.php
+++ b/fp-includes/core/core.date.php
@@ -1,103 +1,282 @@
 <?php
-	
-	date_default_timezone_set('UTC');
+date_default_timezone_set('UTC');
 
-	function date_strformat($format, $timestamp=0) {
-		global $lang;
+function date_strformat($format, $timestamp = 0) {
+	global $lang;
 
-		// D l day
-		
-		if ( strpos($format, '%a') !== false ) {
-			$i = strftime('%w', $timestamp);
-			$format = str_replace('%a', $lang['date']['weekday_abbr'][$i], $format);
-		}
-		
-		if ( strpos($format, '%A') !== false  ) {
-			$i = strftime('%w', $timestamp);
-			$format = str_replace('%A', $lang['date']['weekday'][$i], $format);
-		}
-		
-		
-		// F M month
-		
-		if ( strpos($format, '%b') !== false  ) {
-			$i = intval(strftime('%m', $timestamp))-1;
-			$format = str_replace('%b', $lang['date']['month_abbr'][$i], $format);
-		}
-		
-		
-		if ( strpos($format, '%B') !== false  ) {
-			$i = intval(strftime('%m', $timestamp))-1;
-			$format = str_replace('%B', $lang['date']['month'][$i], $format);
-		}
-		
-			if (DIRECTORY_SEPARATOR == '\\') {
-			$_win_from = array('%D',       '%h', '%n', '%r',          '%R',    '%t', '%T');
-			$_win_to   = array('%m/%d/%y', '%b', "\n", '%I:%M:%S %p', '%H:%M', "\t", '%H:%M:%S');
-				if (strpos($format, '%e') !== false) {
-					$_win_from[] = '%e';
-					$_win_to[]   = sprintf('%\' 2d', date('j', $timestamp));
-				}
-				if (strpos($format, '%l') !== false) {
-					$_win_from[] = '%l';
-					$_win_to[]   = sprintf('%\' 2d', date('h', $timestamp));
-				}
-				$format = str_replace($_win_from, $_win_to, $format);
-			}
-		
-		return strftime($format, $timestamp);
-	
-		
+	// D l day
+
+	if (strpos($format, '%a') !== false) {
+		$i = strftime_replacement('%w', $timestamp);
+		$format = str_replace('%a', $lang ['date'] ['weekday_abbr'] [$i], $format);
 	}
 
-	function date_time($offset=null) {
-		global $fp_config;
-		if (is_null($offset)) {
-			$offset = $fp_config['locale']['timeoffset'];
+	if (strpos($format, '%A') !== false) {
+		$i = strftime_replacement('%w', $timestamp);
+		$format = str_replace('%A', $lang ['date'] ['weekday'] [$i], $format);
+	}
+
+	// F M month
+
+	if (strpos($format, '%b') !== false) {
+		$i = intval(strftime_replacement('%m', $timestamp)) - 1;
+		$format = str_replace('%b', $lang ['date'] ['month_abbr'] [$i], $format);
+	}
+
+	if (strpos($format, '%B') !== false) {
+		$i = intval(strftime_replacement('%m', $timestamp)) - 1;
+		$format = str_replace('%B', $lang ['date'] ['month'] [$i], $format);
+	}
+
+	if (DIRECTORY_SEPARATOR == '\\') {
+		$_win_from = array(
+			'%D',
+			'%h',
+			'%n',
+			'%r',
+			'%R',
+			'%t',
+			'%T'
+		);
+		$_win_to = array(
+			'%m/%d/%y',
+			'%b',
+			"\n",
+			'%I:%M:%S %p',
+			'%H:%M',
+			"\t",
+			'%H:%M:%S'
+		);
+		if (strpos($format, '%e') !== false) {
+			$_win_from [] = '%e';
+			$_win_to [] = sprintf('%\' 2d', date('j', $timestamp));
 		}
-		$timestamp = time();
-		return $timestamp + $offset * 3600;
+		if (strpos($format, '%l') !== false) {
+			$_win_from [] = '%l';
+			$_win_to [] = sprintf('%\' 2d', date('h', $timestamp));
+		}
+		$format = str_replace($_win_from, $_win_to, $format);
 	}
 
+	return strftime_replacement($format, $timestamp);
+}
 
-	/*
-	function date_now($offset=0) {	
-		$timestamp = gmtime();
-		$time_stamp = intval($timestamp) + intval($offset) * 60 * 60;
-		return date($format, $time_stamp);
-	
+function date_time($offset = null) {
+	global $fp_config;
+	if (is_null($offset)) {
+		$offset = $fp_config ['locale'] ['timeoffset'];
 	}
-	*/
-	
-	// I really DON'T LIKE THIS, looks like an hack, yech...
-	// Takes filename and extension as a parameter, strips
-	// alphabetic chars (ascii) from filename and "parses" the date;
-	// In fact it's just a substr, counting on the fact filename should be
-	// "prefix%y%m%d-%H%M%S.ext"
-	function date_from_id($id) {
-			
-			
-			$strdate = substr($id, -13);
-			
-			if (!preg_match('/[0-9]{6}-[0-9]{6}/', $strdate))
-				return array();
-			
-			$arr[ 'y' ] = substr($strdate, 0, 2);
-			$arr[ 'm' ] = substr($strdate, 2, 2);
-			$arr[ 'd' ] = substr($strdate, 4, 2);
-			
-			$arr[ 'H' ] = substr($strdate, 7, 2);
-			$arr[ 'M' ] = substr($strdate, 9, 2);
-			$arr[ 'S' ] = substr($strdate, 11, 2);
-			
-			$arr['ymd'] = $arr['y'] . $arr['m'] . $arr['d'];
-			$arr['HMS'] = $arr['H'] . $arr['M'] . $arr['S'];
-			
-			$arr['time'] = mktime($arr['H'], $arr['M'], $arr['S'],
-					$arr['m'], $arr['d'], $arr['y']);
-			
-		return $arr;
-		
+	$timestamp = time();
+	return $timestamp + $offset * 3600;
+}
+
+/*
+ * function date_now($offset=0) {
+ * $timestamp = gmtime();
+ * $time_stamp = intval($timestamp) + intval($offset) * 60 * 60;
+ * return date($format, $time_stamp);
+ *
+ * }
+ */
+
+// I really DON'T LIKE THIS, looks like an hack, yech...
+// Takes filename and extension as a parameter, strips
+// alphabetic chars (ascii) from filename and "parses" the date;
+// In fact it's just a substr, counting on the fact filename should be
+// "prefix%y%m%d-%H%M%S.ext"
+function date_from_id($id) {
+	$strdate = substr($id, -13);
+
+	if (!preg_match('/[0-9]{6}-[0-9]{6}/', $strdate))
+		return array();
+
+	$arr ['y'] = substr($strdate, 0, 2);
+	$arr ['m'] = substr($strdate, 2, 2);
+	$arr ['d'] = substr($strdate, 4, 2);
+
+	$arr ['H'] = substr($strdate, 7, 2);
+	$arr ['M'] = substr($strdate, 9, 2);
+	$arr ['S'] = substr($strdate, 11, 2);
+
+	$arr ['ymd'] = $arr ['y'] . $arr ['m'] . $arr ['d'];
+	$arr ['HMS'] = $arr ['H'] . $arr ['M'] . $arr ['S'];
+
+	$arr ['time'] = mktime($arr ['H'], $arr ['M'], $arr ['S'], $arr ['m'], $arr ['d'], $arr ['y']);
+
+	return $arr;
+}
+
+/**
+ * Locale-formatted strftime using \IntlDateFormatter (PHP 8.1 compatible)
+ * This provides a cross-platform alternative to strftime() for when it will be removed from PHP.
+ * Note that output can be slightly different between libc sprintf and this function as it is using ICU.
+ *
+ * Usage:
+ * use function \PHP81_BC\strftime;
+ * echo strftime('%A %e %B %Y %X', new \DateTime('2021-09-28 00:00:00'), 'fr_FR');
+ *
+ * Original use:
+ * \setlocale('fr_FR.UTF-8', LC_TIME);
+ * echo \strftime('%A %e %B %Y %X', strtotime('2021-09-28 00:00:00'));
+ *
+ * @param string $format
+ *        	Date format
+ * @param integer|string|DateTime $timestamp
+ *        	Timestamp
+ * @return string
+ * @author BohwaZ <https://bohwaz.net/>
+ */
+function strftime_replacement(string $format, $timestamp = null, ?string $locale = null): string {
+	if (null === $timestamp) {
+		$timestamp = new \DateTime();
+	} elseif (is_numeric($timestamp)) {
+		$timestamp = date_create('@' . $timestamp);
+
+		if ($timestamp) {
+			$timestamp->setTimezone(new \DateTimezone(date_default_timezone_get()));
+		}
+	} elseif (is_string($timestamp)) {
+		$timestamp = date_create($timestamp);
 	}
-	
-?>
+
+	if (!($timestamp instanceof \DateTimeInterface)) {
+		throw new \InvalidArgumentException('$timestamp argument is neither a valid UNIX timestamp, a valid date-time string or a DateTime object.');
+	}
+
+	$locale = substr((string) $locale, 0, 5);
+
+	$intl_formats = [
+		'%a' => 'EEE', // An abbreviated textual representation of the day Sun through Sat
+		'%A' => 'EEEE', // A full textual representation of the day Sunday through Saturday
+		'%b' => 'MMM', // Abbreviated month name, based on the locale Jan through Dec
+		'%B' => 'MMMM', // Full month name, based on the locale January through December
+		'%h' => 'MMM' // Abbreviated month name, based on the locale (an alias of %b) Jan through Dec
+	];
+
+	$intl_formatter = function (\DateTimeInterface $timestamp, string $format) use ($intl_formats, $locale) {
+		$tz = $timestamp->getTimezone();
+		$date_type = \IntlDateFormatter::FULL;
+		$time_type = \IntlDateFormatter::FULL;
+		$pattern = '';
+
+		// %c = Preferred date and time stamp based on locale
+		// Example: Tue Feb 5 00:45:10 2009 for February 5, 2009 at 12:45:10 AM
+		if ($format == '%c') {
+			$date_type = \IntlDateFormatter::LONG;
+			$time_type = \IntlDateFormatter::SHORT;
+		} // %x = Preferred date representation based on locale, without the time
+		  // Example: 02/05/09 for February 5, 2009
+		elseif ($format == '%x') {
+			$date_type = \IntlDateFormatter::SHORT;
+			$time_type = \IntlDateFormatter::NONE;
+		} // Localized time format
+		elseif ($format == '%X') {
+			$date_type = \IntlDateFormatter::NONE;
+			$time_type = \IntlDateFormatter::MEDIUM;
+		} else {
+			$pattern = $intl_formats [$format];
+		}
+
+		return (new \IntlDateFormatter($locale, $date_type, $time_type, $tz, null, $pattern))->format($timestamp);
+	};
+
+	// Same order as https://www.php.net/manual/en/function.strftime.php
+	$translation_table = [
+		// Day
+		'%a' => $intl_formatter,
+		'%A' => $intl_formatter,
+		'%d' => 'd',
+		'%e' => function ($timestamp) {
+			return sprintf('% 2u', $timestamp->format('j'));
+		},
+		'%j' => function ($timestamp) {
+			// Day number in year, 001 to 366
+			return sprintf('%03d', $timestamp->format('z') + 1);
+		},
+		'%u' => 'N',
+		'%w' => 'w',
+
+		// Week
+		'%U' => function ($timestamp) {
+			// Number of weeks between date and first Sunday of year
+			$day = new \DateTime(sprintf('%d-01 Sunday', $timestamp->format('Y')));
+			return sprintf('%02u', 1 + ($timestamp->format('z') - $day->format('z')) / 7);
+		},
+		'%V' => 'W',
+		'%W' => function ($timestamp) {
+			// Number of weeks between date and first Monday of year
+			$day = new \DateTime(sprintf('%d-01 Monday', $timestamp->format('Y')));
+			return sprintf('%02u', 1 + ($timestamp->format('z') - $day->format('z')) / 7);
+		},
+
+		// Month
+		'%b' => $intl_formatter,
+		'%B' => $intl_formatter,
+		'%h' => $intl_formatter,
+		'%m' => 'm',
+
+		// Year
+		'%C' => function ($timestamp) {
+			// Century (-1): 19 for 20th century
+			return floor($timestamp->format('Y') / 100);
+		},
+		'%g' => function ($timestamp) {
+			return substr($timestamp->format('o'), -2);
+		},
+		'%G' => 'o',
+		'%y' => 'y',
+		'%Y' => 'Y',
+
+		// Time
+		'%H' => 'H',
+		'%k' => function ($timestamp) {
+			return sprintf('% 2u', $timestamp->format('G'));
+		},
+		'%I' => 'h',
+		'%l' => function ($timestamp) {
+			return sprintf('% 2u', $timestamp->format('g'));
+		},
+		'%M' => 'i',
+		'%p' => 'A', // AM PM (this is reversed on purpose!)
+		'%P' => 'a', // am pm
+		'%r' => 'h:i:s A', // %I:%M:%S %p
+		'%R' => 'H:i', // %H:%M
+		'%S' => 's',
+		'%T' => 'H:i:s', // %H:%M:%S
+		'%X' => $intl_formatter, // Preferred time representation based on locale, without the date
+
+		// Timezone
+		'%z' => 'O',
+		'%Z' => 'T',
+
+		// Time and Date Stamps
+		'%c' => $intl_formatter,
+		'%D' => 'm/d/Y',
+		'%F' => 'Y-m-d',
+		'%s' => 'U',
+		'%x' => $intl_formatter
+	];
+
+	$out = preg_replace_callback('/(?<!%)(%[a-zA-Z])/', function ($match) use ($translation_table, $timestamp) {
+		if ($match [1] == '%n') {
+			return "\n";
+		} elseif ($match [1] == '%t') {
+			return "\t";
+		}
+
+		if (!isset($translation_table [$match [1]])) {
+			throw new \InvalidArgumentException(sprintf('Format "%s" is unknown in time format', $match [1]));
+		}
+
+		$replace = $translation_table [$match [1]];
+
+		if (is_string($replace)) {
+			return $timestamp->format($replace);
+		} else {
+			return $replace($timestamp, $match [1]);
+		}
+	}, $format);
+
+	$out = str_replace('%%', '%', $out);
+	return $out;
+}
\ No newline at end of file