Initial v14 fixes

module/data/activeEffect/baseEffect.mjs

@@ -12,11 +12,27 @@
  *  "Anything that uses another data model value as its value": +1 - Effects that increase traits have to be calculated first at Base priority. (EX: Raise evasion by half your agility)
  */
 
-export default class BaseEffect extends foundry.abstract.TypeDataModel {
+export default class BaseEffect extends foundry.data.ActiveEffectTypeDataModel {
     static defineSchema() {
         const fields = foundry.data.fields;
 
         return {
+            ...super.defineSchema(),
+            changes: new fields.ArrayField(
+                new fields.SchemaField({
+                    key: new fields.StringField({ required: true }),
+                    type: new fields.StringField({
+                        required: true,
+                        blank: false,
+                        choices: CONFIG.DH.GENERAL.activeEffectModes,
+                        initial: CONFIG.DH.GENERAL.activeEffectModes.add.id,
+                        validate: BaseEffect.#validateType
+                    }),
+                    value: new fields.AnyField({ required: true, nullable: true, serializable: true, initial: '' }),
+                    phase: new fields.StringField({ required: true, blank: false, initial: 'initial' }),
+                    priority: new fields.NumberField()
+                })
+            ),
             rangeDependence: new fields.SchemaField({
                 enabled: new fields.BooleanField({
                     required: true,
@@ -45,6 +61,23 @@ export default class BaseEffect extends foundry.abstract.TypeDataModel {
         };
     }
 
+    /**
+     * Validate that an {@link EffectChangeData#type} string is well-formed.
+     * @param {string} type The string to be validated
+     * @returns {true}
+     * @throws {Error} An error if the type string is malformed
+     */
+    static #validateType(type) {
+        if (type.length < 3) throw new Error('must be at least three characters long');
+        if (!/^custom\.-?\d+$/.test(type) && !type.split('.').every(s => /^[a-z0-9]+$/i.test(s))) {
+            throw new Error(
+                'A change type must either be a sequence of dot-delimited, alpha-numeric substrings or of the form' +
+                    ' "custom.{number}"'
+            );
+        }
+        return true;
+    }
+
     static getDefaultObject() {
         return {
             name: 'New Effect',

module/data/activeEffect/beastformEffect.mjs

@@ -5,6 +5,7 @@ export default class BeastformEffect extends BaseEffect {
     static defineSchema() {
         const fields = foundry.data.fields;
         return {
+            ...super.defineSchema(),
             characterTokenData: new fields.SchemaField({
                 usesDynamicToken: new fields.BooleanField({ initial: false }),
                 tokenImg: new fields.FilePathField({