diff --git a/phpmon-tests/Versions/PhpVersionNumberTest.swift b/phpmon-tests/Versions/PhpVersionNumberTest.swift
index 1f4b8c4..f8b904a 100644
--- a/phpmon-tests/Versions/PhpVersionNumberTest.swift
+++ b/phpmon-tests/Versions/PhpVersionNumberTest.swift
@@ -8,6 +8,7 @@
 
 import XCTest
 
+// swiftlint:disable type_body_length
 class PhpVersionNumberTest: XCTestCase {
 
     func testCanDeconstructPhpVersion() throws {
@@ -287,4 +288,76 @@ class PhpVersionNumberTest: XCTestCase {
                 .make(from: ["7.3.1", "7.2.9"]).all
         )
     }
+
+    func testCanCheckLessThanOrEqualConstraints() throws {
+        XCTAssertEqual(
+            PhpVersionNumberCollection
+                .make(from: ["7.4", "7.3", "7.2", "7.1", "7.0"])
+                .matching(constraint: "<=7.2", strict: true),
+            PhpVersionNumberCollection
+                .make(from: ["7.2", "7.1", "7.0"]).all
+        )
+
+        XCTAssertEqual(
+            PhpVersionNumberCollection
+                .make(from: ["7.4", "7.3", "7.2", "7.1", "7.0"])
+                .matching(constraint: "<=7.2.0", strict: true),
+            PhpVersionNumberCollection
+                .make(from: ["7.2", "7.1", "7.0"]).all
+        )
+
+        // Strict check (>7.2.5 is too new for 7.2 which resolves to 7.2.0)
+        XCTAssertEqual(
+            PhpVersionNumberCollection
+                .make(from: ["7.4", "7.3", "7.2", "7.1", "7.0"])
+                .matching(constraint: "<=7.2.5", strict: true),
+            PhpVersionNumberCollection
+                .make(from: ["7.2", "7.1", "7.0"]).all
+        )
+
+        // Non-strict check (ignoring patch has no effect)
+        XCTAssertEqual(
+            PhpVersionNumberCollection
+                .make(from: ["7.4", "7.3", "7.2", "7.1", "7.0"])
+                .matching(constraint: "<=7.2.5", strict: false),
+            PhpVersionNumberCollection
+                .make(from: ["7.2", "7.1", "7.0"]).all
+        )
+    }
+
+    func testCanCheckLessThanConstraints() throws {
+        XCTAssertEqual(
+            PhpVersionNumberCollection
+                .make(from: ["7.4", "7.3", "7.2", "7.1", "7.0"])
+                .matching(constraint: "<7.2", strict: true),
+            PhpVersionNumberCollection
+                .make(from: ["7.1", "7.0"]).all
+        )
+
+        XCTAssertEqual(
+            PhpVersionNumberCollection
+                .make(from: ["7.4", "7.3", "7.2", "7.1", "7.0"])
+                .matching(constraint: "<7.2.0", strict: true),
+            PhpVersionNumberCollection
+                .make(from: ["7.1", "7.0"]).all
+        )
+
+        // Strict check (>7.2.5 is too new for 7.2 which resolves to 7.2.0)
+        XCTAssertEqual(
+            PhpVersionNumberCollection
+                .make(from: ["7.4", "7.3", "7.2", "7.1", "7.0"])
+                .matching(constraint: "<7.2.5", strict: true),
+            PhpVersionNumberCollection
+                .make(from: ["7.2", "7.1", "7.0"]).all
+        )
+
+        // Non-strict check (patch resolves to 7.2.999, which is bigger than 7.2.5)
+        XCTAssertEqual(
+            PhpVersionNumberCollection
+                .make(from: ["7.4", "7.3", "7.2", "7.1", "7.0"])
+                .matching(constraint: "<7.2.5", strict: false),
+            PhpVersionNumberCollection
+                .make(from: ["7.1", "7.0"]).all
+        )
+    }
 }
diff --git a/phpmon/Common/PHP/PHP Version/PhpVersionNumber.swift b/phpmon/Common/PHP/PHP Version/PhpVersionNumber.swift
index 398285c..c262b2c 100644
--- a/phpmon/Common/PHP/PHP Version/PhpVersionNumber.swift	
+++ b/phpmon/Common/PHP/PHP Version/PhpVersionNumber.swift	
@@ -87,6 +87,14 @@ public struct PhpVersionNumberCollection: Equatable {
             return self.versions.filter { $0.isNewerThan(version, strict) }
         }
 
+        if let version = PhpVersionNumber.make(from: constraint, type: .smallerThanOrEqual) {
+            return self.versions.filter { $0.isSameAs(version, strict) || $0.isOlderThan(version, strict)}
+        }
+
+        if let version = PhpVersionNumber.make(from: constraint, type: .smallerThan) {
+            return self.versions.filter { $0.isOlderThan(version, strict)}
+        }
+
         return []
     }
 }
@@ -120,12 +128,8 @@ public struct PhpVersionNumber: Equatable, Hashable {
         case tildeVersionRange = #"^~(?<major>\d+).(?<minor>\d+).?(?<patch>\d+)?\z"#
         case greaterThanOrEqual = #"^>=(?<major>\d+).(?<minor>\d+).?(?<patch>\d+)?\z"#
         case greaterThan = #"^>(?<major>\d+).(?<minor>\d+).?(?<patch>\d+)?\z"#
-
-        // TODO: (6.0) Handle these cases (even though I suspect these are uncommon)
-        /*
         case smallerThanOrEqual = #"^<=(?<major>\d+).(?<minor>\d+).?(?<patch>\d+)?\z"#
         case smallerThan = #"^<(?<major>\d+).(?<minor>\d+).?(?<patch>\d+)?\z"#
-        */
     }
 
     public static func parse(_ text: String) throws -> Self {
@@ -179,6 +183,15 @@ public struct PhpVersionNumber: Equatable, Hashable {
         )
     }
 
+    internal func isOlderThan(_ version: PhpVersionNumber, _ strict: Bool) -> Bool {
+        return (
+            self.major < version.major ||
+            self.major == version.major && self.minor < version.minor ||
+            self.major == version.major && self.minor == version.minor
+            && self.patch(strict) < version.patch(strict)
+        )
+    }
+
     internal func hasNewerMinorVersionOrPatch(_ version: PhpVersionNumber, _ strict: Bool) -> Bool {
         return self.major == version.major &&
         (