diff --git a/src/Aggregation/AbstractAggregation.php b/src/Aggregation/AbstractAggregation.php
index 0f06504016..914274396f 100644
--- a/src/Aggregation/AbstractAggregation.php
+++ b/src/Aggregation/AbstractAggregation.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 use Elastica\Exception\InvalidException;
diff --git a/src/Aggregation/AbstractSimpleAggregation.php b/src/Aggregation/AbstractSimpleAggregation.php
index ad836c3ef9..7168a70eb3 100644
--- a/src/Aggregation/AbstractSimpleAggregation.php
+++ b/src/Aggregation/AbstractSimpleAggregation.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 use Elastica\Exception\InvalidException;
diff --git a/src/Aggregation/AbstractTermsAggregation.php b/src/Aggregation/AbstractTermsAggregation.php
index bd1c416044..31c6193e98 100644
--- a/src/Aggregation/AbstractTermsAggregation.php
+++ b/src/Aggregation/AbstractTermsAggregation.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/AdjacencyMatrix.php b/src/Aggregation/AdjacencyMatrix.php
index add0f4afa0..4d20b3d97a 100644
--- a/src/Aggregation/AdjacencyMatrix.php
+++ b/src/Aggregation/AdjacencyMatrix.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 use Elastica\Query\AbstractQuery;
diff --git a/src/Aggregation/AutoDateHistogram.php b/src/Aggregation/AutoDateHistogram.php
index 63b7a9d086..f38646b110 100644
--- a/src/Aggregation/AutoDateHistogram.php
+++ b/src/Aggregation/AutoDateHistogram.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 use Elastica\Aggregation\Traits\MissingTrait;
diff --git a/src/Aggregation/Avg.php b/src/Aggregation/Avg.php
index ddd5d6d448..17849ff064 100644
--- a/src/Aggregation/Avg.php
+++ b/src/Aggregation/Avg.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/AvgBucket.php b/src/Aggregation/AvgBucket.php
index 7571f2121b..387b5f318a 100644
--- a/src/Aggregation/AvgBucket.php
+++ b/src/Aggregation/AvgBucket.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/BucketScript.php b/src/Aggregation/BucketScript.php
index 14c2998ab4..a1e0f7959b 100644
--- a/src/Aggregation/BucketScript.php
+++ b/src/Aggregation/BucketScript.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/BucketSelector.php b/src/Aggregation/BucketSelector.php
index 1627e07a32..160d16950b 100644
--- a/src/Aggregation/BucketSelector.php
+++ b/src/Aggregation/BucketSelector.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/Cardinality.php b/src/Aggregation/Cardinality.php
index 56009d5c8e..ccb1487cea 100644
--- a/src/Aggregation/Cardinality.php
+++ b/src/Aggregation/Cardinality.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/Children.php b/src/Aggregation/Children.php
index 2def12b4e0..7e4bb4f310 100644
--- a/src/Aggregation/Children.php
+++ b/src/Aggregation/Children.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/Composite.php b/src/Aggregation/Composite.php
index cd0a328f60..e46b0ea7cd 100644
--- a/src/Aggregation/Composite.php
+++ b/src/Aggregation/Composite.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 class Composite extends AbstractAggregation
diff --git a/src/Aggregation/CumulativeSum.php b/src/Aggregation/CumulativeSum.php
index 397a01dfbd..a93a610b46 100644
--- a/src/Aggregation/CumulativeSum.php
+++ b/src/Aggregation/CumulativeSum.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/DateHistogram.php b/src/Aggregation/DateHistogram.php
index 208acb72e9..39e6398a3c 100644
--- a/src/Aggregation/DateHistogram.php
+++ b/src/Aggregation/DateHistogram.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/DateRange.php b/src/Aggregation/DateRange.php
index 250feb6312..6c2ef65ad3 100644
--- a/src/Aggregation/DateRange.php
+++ b/src/Aggregation/DateRange.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/Derivative.php b/src/Aggregation/Derivative.php
index a26dbd5610..cb9b22132d 100644
--- a/src/Aggregation/Derivative.php
+++ b/src/Aggregation/Derivative.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/DiversifiedSampler.php b/src/Aggregation/DiversifiedSampler.php
index 40e30bbf5b..1dfa1106ff 100755
--- a/src/Aggregation/DiversifiedSampler.php
+++ b/src/Aggregation/DiversifiedSampler.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/ExtendedStats.php b/src/Aggregation/ExtendedStats.php
index 5f0f17a5ce..a7cdfdee8c 100644
--- a/src/Aggregation/ExtendedStats.php
+++ b/src/Aggregation/ExtendedStats.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/ExtendedStatsBucket.php b/src/Aggregation/ExtendedStatsBucket.php
index 8bd3cddf67..66475516a4 100644
--- a/src/Aggregation/ExtendedStatsBucket.php
+++ b/src/Aggregation/ExtendedStatsBucket.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/Filter.php b/src/Aggregation/Filter.php
index e3fc9e5d16..74d1c749d6 100644
--- a/src/Aggregation/Filter.php
+++ b/src/Aggregation/Filter.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 use Elastica\Exception\InvalidException;
diff --git a/src/Aggregation/Filters.php b/src/Aggregation/Filters.php
index 4adf573062..371ceca049 100644
--- a/src/Aggregation/Filters.php
+++ b/src/Aggregation/Filters.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 use Elastica\Exception\InvalidException;
diff --git a/src/Aggregation/GapPolicyInterface.php b/src/Aggregation/GapPolicyInterface.php
index a34bee9607..1d175fd339 100644
--- a/src/Aggregation/GapPolicyInterface.php
+++ b/src/Aggregation/GapPolicyInterface.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 use Elastica\Aggregation\Traits\GapPolicyTrait;
diff --git a/src/Aggregation/GeoBounds.php b/src/Aggregation/GeoBounds.php
index f2aeade669..1c4a1a1b6b 100644
--- a/src/Aggregation/GeoBounds.php
+++ b/src/Aggregation/GeoBounds.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/GeoCentroid.php b/src/Aggregation/GeoCentroid.php
index 6cbbec08e7..b151a5375d 100644
--- a/src/Aggregation/GeoCentroid.php
+++ b/src/Aggregation/GeoCentroid.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/GeoDistance.php b/src/Aggregation/GeoDistance.php
index a85309bbbf..7f98e112c9 100644
--- a/src/Aggregation/GeoDistance.php
+++ b/src/Aggregation/GeoDistance.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 use Elastica\Exception\InvalidException;
diff --git a/src/Aggregation/GeohashGrid.php b/src/Aggregation/GeohashGrid.php
index 1d1f4c18e4..bf90d001c3 100644
--- a/src/Aggregation/GeohashGrid.php
+++ b/src/Aggregation/GeohashGrid.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
@@ -46,7 +48,7 @@ public function setField(string $field): self
     public function setPrecision($precision): self
     {
         if (!\is_int($precision) && !\is_string($precision)) {
-            throw new \TypeError(\sprintf('Argument 1 passed to "%s()" must be of type int|string, %s given.', __METHOD__, \is_object($precision) ? \get_class($precision) : \gettype($precision)));
+            throw new \TypeError(\sprintf('Argument 1 passed to "%s()" must be of type int|string, %s given.', __METHOD__, \is_object($precision) ? $precision::class : \gettype($precision)));
         }
 
         return $this->setParam('precision', $precision);
diff --git a/src/Aggregation/GeotileGridAggregation.php b/src/Aggregation/GeotileGridAggregation.php
index aa41687313..aa2b6ec2cc 100644
--- a/src/Aggregation/GeotileGridAggregation.php
+++ b/src/Aggregation/GeotileGridAggregation.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/GlobalAggregation.php b/src/Aggregation/GlobalAggregation.php
index 365c08ea27..9ab9ccb088 100644
--- a/src/Aggregation/GlobalAggregation.php
+++ b/src/Aggregation/GlobalAggregation.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/Histogram.php b/src/Aggregation/Histogram.php
index d951e9f3bd..89be9cad4e 100644
--- a/src/Aggregation/Histogram.php
+++ b/src/Aggregation/Histogram.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/IpRange.php b/src/Aggregation/IpRange.php
index ac78dcdbd9..a44d4805dd 100644
--- a/src/Aggregation/IpRange.php
+++ b/src/Aggregation/IpRange.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 use Elastica\Exception\InvalidException;
diff --git a/src/Aggregation/Max.php b/src/Aggregation/Max.php
index c97475c6c6..a0c7a21746 100644
--- a/src/Aggregation/Max.php
+++ b/src/Aggregation/Max.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/Min.php b/src/Aggregation/Min.php
index 97114e6d5f..8fdc482131 100644
--- a/src/Aggregation/Min.php
+++ b/src/Aggregation/Min.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/Missing.php b/src/Aggregation/Missing.php
index c1de19e3d4..aae6808ac1 100644
--- a/src/Aggregation/Missing.php
+++ b/src/Aggregation/Missing.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/Nested.php b/src/Aggregation/Nested.php
index 6324952f83..1a7bf37443 100644
--- a/src/Aggregation/Nested.php
+++ b/src/Aggregation/Nested.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/NormalizeAggregation.php b/src/Aggregation/NormalizeAggregation.php
index 536900d211..398b1853ec 100644
--- a/src/Aggregation/NormalizeAggregation.php
+++ b/src/Aggregation/NormalizeAggregation.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/ParentAggregation.php b/src/Aggregation/ParentAggregation.php
index f8610de6f0..2d5b971e92 100644
--- a/src/Aggregation/ParentAggregation.php
+++ b/src/Aggregation/ParentAggregation.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/Percentiles.php b/src/Aggregation/Percentiles.php
index 8fc717f6ea..7b1ac27d64 100644
--- a/src/Aggregation/Percentiles.php
+++ b/src/Aggregation/Percentiles.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/PercentilesBucket.php b/src/Aggregation/PercentilesBucket.php
index c0d7e63464..607ced188c 100644
--- a/src/Aggregation/PercentilesBucket.php
+++ b/src/Aggregation/PercentilesBucket.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/Range.php b/src/Aggregation/Range.php
index 4f92495689..785d2ac133 100644
--- a/src/Aggregation/Range.php
+++ b/src/Aggregation/Range.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 use Elastica\Exception\InvalidException;
diff --git a/src/Aggregation/ReverseNested.php b/src/Aggregation/ReverseNested.php
index b1f059451e..7bf58bafdc 100644
--- a/src/Aggregation/ReverseNested.php
+++ b/src/Aggregation/ReverseNested.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/Sampler.php b/src/Aggregation/Sampler.php
index c4a944f5b8..f683e4cf17 100644
--- a/src/Aggregation/Sampler.php
+++ b/src/Aggregation/Sampler.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/ScriptedMetric.php b/src/Aggregation/ScriptedMetric.php
index dbae414940..ee3dbc2c71 100644
--- a/src/Aggregation/ScriptedMetric.php
+++ b/src/Aggregation/ScriptedMetric.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/SerialDiff.php b/src/Aggregation/SerialDiff.php
index 79c1b187ef..7af527c2c1 100644
--- a/src/Aggregation/SerialDiff.php
+++ b/src/Aggregation/SerialDiff.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/SignificantTerms.php b/src/Aggregation/SignificantTerms.php
index 77dff1d202..f7237504ec 100644
--- a/src/Aggregation/SignificantTerms.php
+++ b/src/Aggregation/SignificantTerms.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 use Elastica\Query\AbstractQuery;
diff --git a/src/Aggregation/Stats.php b/src/Aggregation/Stats.php
index 1dc5fbda1e..5e7741cdba 100644
--- a/src/Aggregation/Stats.php
+++ b/src/Aggregation/Stats.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/StatsBucket.php b/src/Aggregation/StatsBucket.php
index b55753d1e7..3bcdf36f09 100644
--- a/src/Aggregation/StatsBucket.php
+++ b/src/Aggregation/StatsBucket.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/Sum.php b/src/Aggregation/Sum.php
index a778cd0cce..f1009e8488 100644
--- a/src/Aggregation/Sum.php
+++ b/src/Aggregation/Sum.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/SumBucket.php b/src/Aggregation/SumBucket.php
index 88bf4b61cd..137b36d817 100644
--- a/src/Aggregation/SumBucket.php
+++ b/src/Aggregation/SumBucket.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/Terms.php b/src/Aggregation/Terms.php
index 385a2bac3b..42e3658bd8 100644
--- a/src/Aggregation/Terms.php
+++ b/src/Aggregation/Terms.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/TopHits.php b/src/Aggregation/TopHits.php
index 269f4c635c..03914bc9f1 100644
--- a/src/Aggregation/TopHits.php
+++ b/src/Aggregation/TopHits.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 use Elastica\Script\AbstractScript;
diff --git a/src/Aggregation/Traits/BucketsPathTrait.php b/src/Aggregation/Traits/BucketsPathTrait.php
index 353230c81b..be70f4875e 100644
--- a/src/Aggregation/Traits/BucketsPathTrait.php
+++ b/src/Aggregation/Traits/BucketsPathTrait.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation\Traits;
 
 trait BucketsPathTrait
diff --git a/src/Aggregation/Traits/GapPolicyTrait.php b/src/Aggregation/Traits/GapPolicyTrait.php
index a5bff2ffb8..3f3ed1b1c1 100644
--- a/src/Aggregation/Traits/GapPolicyTrait.php
+++ b/src/Aggregation/Traits/GapPolicyTrait.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation\Traits;
 
 use Elastica\Aggregation\GapPolicyInterface;
diff --git a/src/Aggregation/Traits/KeyedTrait.php b/src/Aggregation/Traits/KeyedTrait.php
index ec1989277c..90f203ac59 100644
--- a/src/Aggregation/Traits/KeyedTrait.php
+++ b/src/Aggregation/Traits/KeyedTrait.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation\Traits;
 
 trait KeyedTrait
diff --git a/src/Aggregation/Traits/MissingTrait.php b/src/Aggregation/Traits/MissingTrait.php
index f71747facb..386d96291e 100644
--- a/src/Aggregation/Traits/MissingTrait.php
+++ b/src/Aggregation/Traits/MissingTrait.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation\Traits;
 
 trait MissingTrait
diff --git a/src/Aggregation/Traits/ShardSizeTrait.php b/src/Aggregation/Traits/ShardSizeTrait.php
index 1394b07b74..31f701bbbf 100644
--- a/src/Aggregation/Traits/ShardSizeTrait.php
+++ b/src/Aggregation/Traits/ShardSizeTrait.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation\Traits;
 
 trait ShardSizeTrait
diff --git a/src/Aggregation/ValueCount.php b/src/Aggregation/ValueCount.php
index 9d7e8426a6..888916b7cf 100644
--- a/src/Aggregation/ValueCount.php
+++ b/src/Aggregation/ValueCount.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 /**
diff --git a/src/Aggregation/WeightedAvg.php b/src/Aggregation/WeightedAvg.php
index a7b6f26aa6..d3cf339d67 100644
--- a/src/Aggregation/WeightedAvg.php
+++ b/src/Aggregation/WeightedAvg.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Elastica\Aggregation;
 
 use Elastica\Exception\InvalidException;