diff --git a/repository/Grease-Pharo110-Slime.package/GRTestAssertionsRule.class/instance/checkMethod..st b/repository/Grease-Pharo110-Slime.package/GRTestAssertionsRule.class/instance/checkMethod..st
deleted file mode 100644
index bab892c3..00000000
--- a/repository/Grease-Pharo110-Slime.package/GRTestAssertionsRule.class/instance/checkMethod..st
+++ /dev/null
@@ -1,7 +0,0 @@
-running
-checkMethod: aContext
-	aContext methodClass isMeta
-		ifTrue: [ ^ self ].
-	(aContext methodClass allSuperclasses includes:(Smalltalk at: #TestCase))
-		ifFalse: [ ^ self ].
-	^ super checkMethod: aContext
\ No newline at end of file
diff --git a/repository/Grease-Pharo110-Slime.package/monticello.meta/categories.st b/repository/Grease-Pharo110-Slime.package/monticello.meta/categories.st
index ff4f5aed..f4dc770b 100644
--- a/repository/Grease-Pharo110-Slime.package/monticello.meta/categories.st
+++ b/repository/Grease-Pharo110-Slime.package/monticello.meta/categories.st
@@ -1 +1 @@
-SystemOrganization addCategory: #'Grease-Pharo110-Slime'!
+self packageOrganizer ensurePackage: #'Grease-Pharo110-Slime' withTags: #()!
diff --git a/repository/Grease-Tests-Pharo-Core.package/GRPharoPlatformTest.class/instance/testCompileIntoClassified.st b/repository/Grease-Tests-Pharo-Core.package/GRPharoPlatformTest.class/instance/testCompileIntoClassified.st
index 112d896b..8fe4388c 100644
--- a/repository/Grease-Tests-Pharo-Core.package/GRPharoPlatformTest.class/instance/testCompileIntoClassified.st
+++ b/repository/Grease-Tests-Pharo-Core.package/GRPharoPlatformTest.class/instance/testCompileIntoClassified.st
@@ -11,5 +11,5 @@ testCompileIntoClassified
 		classified: protocol.
 	
 	[ self assert: (self class selectors includes: selector).
-	selectors := self class organization listAtCategoryNamed: protocol.
+	selectors := self class selectorsInProtocol: protocol.
 	self assert: selectors = (Array with: selector) ] ensure: [ self class removeSelector: selector ]
\ No newline at end of file
diff --git a/repository/Grease-Tests-Pharo-Core.package/monticello.meta/categories.st b/repository/Grease-Tests-Pharo-Core.package/monticello.meta/categories.st
index 8f89143a..7bce97a3 100644
--- a/repository/Grease-Tests-Pharo-Core.package/monticello.meta/categories.st
+++ b/repository/Grease-Tests-Pharo-Core.package/monticello.meta/categories.st
@@ -1 +1 @@
-SystemOrganization addCategory: #'Grease-Tests-Pharo-Core'!
+self packageOrganizer ensurePackage: #'Grease-Tests-Pharo-Core' withTags: #()!
diff --git a/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/defineSubClassOf..st b/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/defineSubClassOf..st
index 92da2de7..fdcf43d7 100644
--- a/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/defineSubClassOf..st
+++ b/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/defineSubClassOf..st
@@ -1,20 +1,4 @@
 accessing-code
 defineSubClassOf: aSuperSymbol
 
-	| class |
-	class := SystemVersion current major >= 12
-		         ifTrue: [
-			         factory make: [ :aBuilder |
-				         aBuilder
-					         superclass: (Smalltalk at: aSuperSymbol);
-					         package: self category ] ]
-		         ifFalse: [
-			         factory
-				         newSubclassOf: (Smalltalk at: aSuperSymbol)
-				         instanceVariableNames: ''
-				         classVariableNames: 'classVarsString'
-				         category: self category ].
-	environment
-		addClass: class;
-		addClass: class classSide.
-	^ class
\ No newline at end of file
+	^ self defineSubClassOf: aSuperSymbol inPackage: self category
\ No newline at end of file
diff --git a/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/defineSubClassOf.inPackage..st b/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/defineSubClassOf.inPackage..st
new file mode 100644
index 00000000..9ad6f16a
--- /dev/null
+++ b/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/defineSubClassOf.inPackage..st
@@ -0,0 +1,20 @@
+accessing-code
+defineSubClassOf: aSuperSymbol inPackage: packageName
+
+	| class |
+	class := SystemVersion current major >= 12
+		         ifTrue: [
+			         factory make: [ :aBuilder |
+				         aBuilder
+					         superclass: (Smalltalk at: aSuperSymbol);
+					         package: packageName ] ]
+		         ifFalse: [
+			         factory
+				         newSubclassOf: (Smalltalk at: aSuperSymbol)
+				         instanceVariableNames: ''
+				         classVariableNames: 'classVarsString'
+				         category: packageName ].
+	environment
+		addClass: class;
+		addClass: class classSide.
+	^ class
\ No newline at end of file
diff --git a/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/testReferencesNotPortableClass.st b/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/testReferencesNotPortableClass.st
index 6c1b5b23..a3070f80 100644
--- a/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/testReferencesNotPortableClass.st
+++ b/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/testReferencesNotPortableClass.st
@@ -2,8 +2,7 @@ tests-block
 testReferencesNotPortableClass
 
 	| class |
-	class := self defineSubClassOf: #GRObject.
-	class category: 'SomeCategory'.
+	class := self defineSubClassOf: #GRObject inPackage: 'SomeCategory'.
 	self compile: 'invalid ^ Semaphore new' in: class.
 	self compile: 'valid ^ GRObject new' in: class.
 	self 
diff --git a/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/testSubclassesNotPortableClass.st b/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/testSubclassesNotPortableClass.st
index 2ced3881..c86dc173 100644
--- a/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/testSubclassesNotPortableClass.st
+++ b/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/testSubclassesNotPortableClass.st
@@ -2,8 +2,7 @@ tests-block
 testSubclassesNotPortableClass
 
 	| class |
-	class := self defineSubClassOf: #Mutex.
-	class category: 'SomeCategory'.
+	class := self defineSubClassOf: #Mutex inPackage: 'SomeCategory'.
 	self 
 		assertRule: GRSubclassesNotPortableClassRule
 		matches: { class }
\ No newline at end of file
diff --git a/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/testTestCaseFailRule.st b/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/testTestCaseFailRule.st
index c4044a19..1fecfedc 100644
--- a/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/testTestCaseFailRule.st
+++ b/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/testTestCaseFailRule.st
@@ -6,5 +6,4 @@ testTestCaseFailRule
 	self compile: 'testMethod self fail' in: class.
 	self 
 		runTransformation: GRTestAssertionsRule
-		changes: #(
-			'testMethod self assert: false' )
\ No newline at end of file
+		changes: #( 'testMethod self assert: false' )
\ No newline at end of file
diff --git a/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/testUsesNotPortableClass.st b/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/testUsesNotPortableClass.st
index 5699c982..f65d00a4 100644
--- a/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/testUsesNotPortableClass.st
+++ b/repository/Grease-Tests-Pharo-Slime.package/GRReSlimeTest.class/instance/testUsesNotPortableClass.st
@@ -2,8 +2,7 @@ tests-block
 testUsesNotPortableClass
 
 	| class |
-	class := self defineSubClassOf: #GRObject.
-	class category: 'SomeCategory'.
+	class := self defineSubClassOf: #GRObject inPackage: 'SomeCategory'.
 	self compile: 'invalid ^ Semaphore new' in: class.
 	self compile: 'valid ^ GRObject new' in: class.
 	self 
diff --git a/repository/Grease-Tests-Pharo-Slime.package/monticello.meta/categories.st b/repository/Grease-Tests-Pharo-Slime.package/monticello.meta/categories.st
index 6c2ac5ef..bb71bcda 100644
--- a/repository/Grease-Tests-Pharo-Slime.package/monticello.meta/categories.st
+++ b/repository/Grease-Tests-Pharo-Slime.package/monticello.meta/categories.st
@@ -1 +1 @@
-SystemOrganization addCategory: #'Grease-Tests-Pharo-Slime'!
+self packageOrganizer ensurePackage: #'Grease-Tests-Pharo-Slime' withTags: #()!