diff --git a/core/dbobjectiterator.php b/core/dbobjectiterator.php
index 85e1e5208..264b57ba3 100644
--- a/core/dbobjectiterator.php
+++ b/core/dbobjectiterator.php
@@ -38,7 +38,7 @@ interface iDBObjectSetIterator extends Countable
 	 *
 	 * @return int
 	 */
-	public function Count();
+	public function Count(): int;
 
 	/**
 	 * Reset the cursor to the first item in the collection. Equivalent to Seek(0)
diff --git a/core/dbobjectset.class.php b/core/dbobjectset.class.php
index 6e70cbc3b..a5c25ab9c 100644
--- a/core/dbobjectset.class.php
+++ b/core/dbobjectset.class.php
@@ -843,7 +843,7 @@ class DBObjectSet implements iDBObjectSetIterator
      * @throws \MySQLException
      * @throws \MySQLHasGoneAwayException
      */
-	public function Count()
+	public function Count(): int
 	{
 		if (is_null($this->m_iNumTotalDBRows))
 		{
diff --git a/core/ormlinkset.class.inc.php b/core/ormlinkset.class.inc.php
index 43d433c12..131a28a14 100644
--- a/core/ormlinkset.class.inc.php
+++ b/core/ormlinkset.class.inc.php
@@ -312,7 +312,7 @@ class ormLinkSet implements iDBObjectSetIterator, Iterator, SeekableIterator
 	 * @throws \CoreUnexpectedValue
 	 * @throws \MySQLException
 	 */
-	public function Count()
+	public function Count(): int
 	{
 		$this->LoadOriginalIds();
 		$iRet = count($this->aPreserved) + count($this->aAdded) + count($this->aModified);
@@ -327,7 +327,7 @@ class ormLinkSet implements iDBObjectSetIterator, Iterator, SeekableIterator
 	 * @throws Exception
 	 * @internal param int $iRow
 	 */
-	public function Seek($iPosition)
+	public function Seek($iPosition): void
 	{
 		$this->LoadOriginalIds();
 
@@ -375,7 +375,7 @@ class ormLinkSet implements iDBObjectSetIterator, Iterator, SeekableIterator
 	 * @throws \MySQLException
 	 * @throws \MySQLHasGoneAwayException
 	 */
-	public function current()
+	public function current(): mixed
 	{
 		$this->LoadOriginalIds();
 
@@ -410,7 +410,7 @@ class ormLinkSet implements iDBObjectSetIterator, Iterator, SeekableIterator
 	 * @throws \CoreUnexpectedValue
 	 * @throws \MySQLException
 	 */
-	public function next()
+	public function next(): void
 	{
 		$this->LoadOriginalIds();
 
@@ -440,7 +440,7 @@ class ormLinkSet implements iDBObjectSetIterator, Iterator, SeekableIterator
 	 * @link http://php.net/manual/en/iterator.key.php
 	 * @return mixed scalar on success, or null on failure.
 	 */
-	public function key()
+	public function key(): mixed
 	{
 		return $this->iCursor;
 	}
@@ -455,7 +455,7 @@ class ormLinkSet implements iDBObjectSetIterator, Iterator, SeekableIterator
 	 * @throws \CoreUnexpectedValue
 	 * @throws \MySQLException
 	 */
-	public function valid()
+	public function valid(): bool
 	{
 		$this->LoadOriginalIds();
 
@@ -473,7 +473,7 @@ class ormLinkSet implements iDBObjectSetIterator, Iterator, SeekableIterator
 	 * @throws \CoreUnexpectedValue
 	 * @throws \MySQLException
 	 */
-	public function rewind()
+	public function rewind(): void
 	{
 	    $this->LoadOriginalIds();
 
diff --git a/core/simplegraph.class.inc.php b/core/simplegraph.class.inc.php
index 979992efb..1c5304d1a 100644
--- a/core/simplegraph.class.inc.php
+++ b/core/simplegraph.class.inc.php
@@ -745,27 +745,27 @@ class RelationTypeIterator implements Iterator
 		}
 	}
 	
-	public function rewind()
+	public function rewind(): void
 	{
 		$this->iCurrentIdx = 0;
 	}
 	
-	public function valid()
+	public function valid(): bool
 	{
 		return array_key_exists($this->iCurrentIdx, $this->aList);
 	}
 	
-	public function next()
+	public function next(): void
 	{
 		$this->iCurrentIdx++;
 	}
 	
-	public function current()
+	public function current(): mixed
 	{
 		return $this->aList[$this->iCurrentIdx];
 	}
 	
-	public function key()
+	public function key(): mixed
 	{
 		return $this->iCurrentIdx;
 	}