diff --git a/ptbposter/ptbposter-2020.clo b/ptbposter/ptbposter-2020.clo
index d91d650af9b5207fbf467af8a863be700ec5ef7a..14aec93a7e7c070fc56d190b430c2792213322c4 100644
--- a/ptbposter/ptbposter-2020.clo
+++ b/ptbposter/ptbposter-2020.clo
@@ -30,7 +30,7 @@
 
 \AtEndPreamble{%
   \setlength\PTB@topmargin{0.193953\PTB@scale@base}%
-  \ifPTBlandscape  % ???
+  \ifPTBlandscape
     \setlength\PTB@framewidth{0.950378471315\PTB@scale@base}%  3215pt (1130mm) (A0) 
     \setlength\PTB@frameheight{0.447\PTB@scale@base}% 1563pt  (549mm) (A0) 
   \else
diff --git a/ptbposter/ptbposter.cls b/ptbposter/ptbposter.cls
index a6a43e457ad95a473aafbb26f1645cc4201511f0..6acf9d8d64fd8e4207fad051bc49b41d956c2c19 100644
--- a/ptbposter/ptbposter.cls
+++ b/ptbposter/ptbposter.cls
@@ -3,7 +3,7 @@
 \setcounter{errorcontextlines}{100}  \listfiles
 
 \NeedsTeXFormat{LaTeX2e}[1999/12/01]
-\ProvidesClass{ptbposter}[2022/09/20 1.0.0 PTB-Poster (RN)]
+\ProvidesClass{ptbposter}[2022/09/20 1.0.1 PTB-Poster (RN)]
     
 \newif\ifPTB@useCMYK \PTB@useCMYKfalse % vorerst 
 \newif\ifPTB@german@  \PTB@german@true
@@ -47,15 +47,11 @@
 \newbox\PTB@tempboxa
 
 \newif\ifPTBlandscape \PTBlandscapefalse
-\newif\ifPTB@XeOrLua \PTB@XeOrLuafalse
 \newif\ifSERIF \SERIFfalse
 \newif\ifMATHSERIF \MATHSERIFfalse
 \newif\ifFIRA \FIRAfalse
 \newif\ifPTB@logo@long@ \PTB@logo@long@true
 
-\RequirePackage{ifluatex,ifxetex}
-\ifxetex\PTB@XeOrLuatrue\else\ifluatex\PTB@XeOrLuatrue\fi\fi
-
 \PassOptionsToPackage{pagesize=false}{typearea}
 \PassOptionsToPackage{paper=a0paper,onecolumn,portrait,driver=none}{geometry}
 
@@ -109,6 +105,11 @@
   \OptionNotUsed
 }
 \DeclareOption{landscape}{%
+  \PTBlandscapetrue
+  \PassOptionsToPackage{\CurrentOption}{geometry}
+}
+\DeclareOption{portrait}{%
+  \PTBlandscapefalse
   \PassOptionsToPackage{\CurrentOption}{geometry}
 }
 \DeclareOption{shortPTBlogo}{%
@@ -149,10 +150,14 @@
   \RequirePackage{blowup}[2022/09/19]
   \ClassNoteNoLine{ptbposter}{%
     Scaling the sheet from size `a0' to size `\PTB@target@size'}%
-  \blowUp{target=\PTB@target@size}
+  \ifPTBlandscape
+    \blowUp{target=\PTB@target@size,landscape}
+  \else
+    \blowUp{target=\PTB@target@size}
+  \fi
 \fi
 
-\ifPTB@XeOrLua
+\iftutex% LuaTeX oder XeTeX
   \input{ptbposter-new-engines.clo}
 \else
   \input{ptbposter-old-engines.clo}