diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 6306b873b..85da972ea 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -33,7 +33,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        xcode: ["16.1", "16.0", "15.4", "15.2"]
+        xcode: ["16.1", "16.0", "15.4"]
         include:
           - xcode: "16.1"
             macos: macos-15
@@ -41,8 +41,6 @@ jobs:
             macos: macos-15
           - xcode: "15.4"
             macos: macos-14
-          - xcode: "15.2"
-            macos: macos-14
     runs-on: ${{ matrix.macos }}
     name: macOS
     steps:
@@ -77,14 +75,12 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        swift: ["6.0", "5.10", "5.9"]
+        swift: ["6.0", "5.10"]
         include:
           - swift: "6.0"
             container: "swift:6.0"
           - swift: "5.10"
             container: "swift:5.10"
-          - swift: "5.9"
-            container: "swift:5.9"
     runs-on: ubuntu-20.04
     container: ${{ matrix.container }}
     name: Linux
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 965f0c7d9..37c2ed261 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ##### Breaking
 
 - Support for installing via CocoaPods has been removed.
+- Removed support for Swift 5.9/Xcode 15.2.
 
 ##### Enhancements
 
diff --git a/Package.swift b/Package.swift
index bc8891520..2b8ff4f3e 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:5.9
+// swift-tools-version:5.10
 import PackageDescription
 
 var dependencies: [Package.Dependency] = [
diff --git a/Sources/BUILD.bazel b/Sources/BUILD.bazel
index 0ffe0c6d2..4c3797712 100644
--- a/Sources/BUILD.bazel
+++ b/Sources/BUILD.bazel
@@ -57,7 +57,6 @@ swift_library(
         "SourceGraph/Mutators/AncestralReferenceEliminator.swift",
         "SourceGraph/Mutators/AssetReferenceRetainer.swift",
         "SourceGraph/Mutators/AssignOnlyPropertyReferenceEliminator.swift",
-        "SourceGraph/Mutators/CapitalSelfFunctionCallRetainer.swift",
         "SourceGraph/Mutators/CodablePropertyRetainer.swift",
         "SourceGraph/Mutators/CodingKeyEnumReferenceBuilder.swift",
         "SourceGraph/Mutators/ComplexPropertyAccessorReferenceBuilder.swift",
diff --git a/Sources/Shared/SwiftVersion.swift b/Sources/Shared/SwiftVersion.swift
index 974502cb1..4a4210fb4 100644
--- a/Sources/Shared/SwiftVersion.swift
+++ b/Sources/Shared/SwiftVersion.swift
@@ -2,7 +2,7 @@ import Extensions
 import Foundation
 
 public struct SwiftVersion {
-    static let minimumVersion = "5.9"
+    static let minimumVersion = "5.10"
 
     public let version: VersionString
     public let fullVersion: String
diff --git a/Sources/SourceGraph/Mutators/CapitalSelfFunctionCallRetainer.swift b/Sources/SourceGraph/Mutators/CapitalSelfFunctionCallRetainer.swift
deleted file mode 100644
index 638b9faa9..000000000
--- a/Sources/SourceGraph/Mutators/CapitalSelfFunctionCallRetainer.swift
+++ /dev/null
@@ -1,28 +0,0 @@
-import Configuration
-import Foundation
-import Shared
-
-/// Retains all constructors on types instantiated via `Self(...)` to workaround false positives caused by a bug in Swift.
-/// https://github.com/apple/swift/issues/64686
-/// https://github.com/peripheryapp/periphery/issues/264
-final class CapitalSelfFunctionCallRetainer: SourceGraphMutator {
-    private let graph: SourceGraph
-    private let swiftVersion: SwiftVersion
-
-    required init(graph: SourceGraph, configuration _: Configuration, swiftVersion: SwiftVersion) {
-        self.graph = graph
-        self.swiftVersion = swiftVersion
-    }
-
-    func mutate() {
-        guard swiftVersion.version.isVersion(lessThan: "5.9") else { return }
-
-        for decl in graph.declarations(ofKinds: [.struct, .class]) {
-            guard decl.hasCapitalSelfFunctionCall else { continue }
-            decl.declarations
-                .lazy
-                .filter { $0.kind == .functionConstructor }
-                .forEach { graph.markRetained($0) }
-        }
-    }
-}
diff --git a/Sources/SourceGraph/SourceGraphMutatorRunner.swift b/Sources/SourceGraph/SourceGraphMutatorRunner.swift
index e9090c65f..f67ddeb58 100644
--- a/Sources/SourceGraph/SourceGraphMutatorRunner.swift
+++ b/Sources/SourceGraph/SourceGraphMutatorRunner.swift
@@ -40,7 +40,6 @@ public final class SourceGraphMutatorRunner {
         StringInterpolationAppendInterpolationRetainer.self,
         PropertyWrapperRetainer.self,
         ResultBuilderRetainer.self,
-        CapitalSelfFunctionCallRetainer.self,
         CodablePropertyRetainer.self,
         ExternalOverrideRetainer.self,
 
diff --git a/Tests/AccessibilityTests/AccessibilityProject/Package.swift b/Tests/AccessibilityTests/AccessibilityProject/Package.swift
index 3ec209552..3cd569cd3 100644
--- a/Tests/AccessibilityTests/AccessibilityProject/Package.swift
+++ b/Tests/AccessibilityTests/AccessibilityProject/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:5.9
+// swift-tools-version:5.10
 import PackageDescription
 
 let package = Package(
diff --git a/Tests/Fixtures/Package.swift b/Tests/Fixtures/Package.swift
index 48b28fe78..56a9d9106 100644
--- a/Tests/Fixtures/Package.swift
+++ b/Tests/Fixtures/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:5.9
+// swift-tools-version:5.10
 import PackageDescription
 
 var targets: [PackageDescription.Target] = [
diff --git a/Tests/SPMTests/SPMProject/Package.swift b/Tests/SPMTests/SPMProject/Package.swift
index b0a76063f..c6260cca7 100644
--- a/Tests/SPMTests/SPMProject/Package.swift
+++ b/Tests/SPMTests/SPMProject/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:5.9
+// swift-tools-version:5.10
 import PackageDescription
 
 let package = Package(
diff --git a/Tests/XcodeTests/UIKitProject/LocalPackages/LocalPackage/Package.swift b/Tests/XcodeTests/UIKitProject/LocalPackages/LocalPackage/Package.swift
index ef0cd7620..3ee3878a6 100644
--- a/Tests/XcodeTests/UIKitProject/LocalPackages/LocalPackage/Package.swift
+++ b/Tests/XcodeTests/UIKitProject/LocalPackages/LocalPackage/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version: 5.9
+// swift-tools-version: 5.10
 import PackageDescription
 
 let package = Package(