diff --git a/packages/base/src/features/OpenUI5Support.ts b/packages/base/src/features/OpenUI5Support.ts
index 8bf7827e5082..8b557dad4075 100644
--- a/packages/base/src/features/OpenUI5Support.ts
+++ b/packages/base/src/features/OpenUI5Support.ts
@@ -165,9 +165,9 @@ class OpenUI5Support {
 			animationMode: config.getAnimationMode(),
 			language: config.getLanguage(),
 			theme: config.getTheme(),
-			themeRoot: config.getThemeRoot(),
+			themeRoot: typeof config.getThemeRoot === "function" ? config.getThemeRoot() : undefined,
 			rtl: config.getRTL(),
-			timezone: config.getTimezone(),
+			timezone: typeof config.getTimezone === "function" ? config.getTimezone() : undefined,
 			calendarType: config.getCalendarType(),
 			formatSettings: {
 				firstDayOfWeek: LocaleData ? LocaleData.getInstance(config.getLocale()).getFirstDayOfWeek() : undefined,
diff --git a/packages/base/src/features/patchPatcher.ts b/packages/base/src/features/patchPatcher.ts
index 051d124902bb..eac76e7c37ac 100644
--- a/packages/base/src/features/patchPatcher.ts
+++ b/packages/base/src/features/patchPatcher.ts
@@ -1,19 +1,30 @@
-type OpenUI5Patcher = {
-	prototype: {
-		_mAttributes: { [key: string]: string },
-		openEnd: () => OpenUI5Patcher,
-	}
+type PatcherTarget = {
+	_mAttributes: { [key: string]: string },
+	openEnd: () => OpenUI5Patcher,
 };
 
-const patchPatcher = (Patcher: OpenUI5Patcher) => {
-	const origOpenEnd = Patcher.prototype.openEnd;
-	Patcher.prototype.openEnd = function openEnd() {
-		if (this._mAttributes.popover) {
+type OpenUI5Patcher = { prototype: PatcherTarget } // newer versions (on prototype)
+	| PatcherTarget; // older versions (on constructor directly)
+
+const patchOpenEnd = (target: PatcherTarget) => {
+	const origOpenEnd = target.openEnd;
+	target.openEnd = function openEnd() {
+		if (this._mAttributes?.popover) {
 			delete this._mAttributes.popover; // The "popover" attribute will be managed externally, don't let Patcher remove it
 		}
 		return origOpenEnd.apply(this);
 	};
 };
 
+const patchPatcher = (Patcher: OpenUI5Patcher) => {
+	// Newer version: properties are on prototype
+	if ("prototype" in Patcher && "openEnd" in Patcher.prototype) {
+		patchOpenEnd(Patcher.prototype);
+	} else if ("openEnd" in Patcher) {
+		// Older version: properties are on constructor directly
+		patchOpenEnd(Patcher);
+	}
+};
+
 export default patchPatcher;
 export type { OpenUI5Patcher };