diff --git a/ptbposter/ptbposter-new-engines.clo b/ptbposter/ptbposter-new-engines.clo
index 7f814fa392ec9c3d94f4727e2c7ec7eda09d4640..2dc9a677763b56ec084cfd99e3d3bbae60690874 100644
--- a/ptbposter/ptbposter-new-engines.clo
+++ b/ptbposter/ptbposter-new-engines.clo
@@ -28,9 +28,14 @@
 \setmathfont{texgyrepagella-math.otf}[math-style=ISO,bold-style=ISO]
 \let\sffamily=\PTBdesignFont
 
-\unimathsetup{partial=upright}
+\unimathsetup{partial=upright}  
 
-\ifPTB@serif\else
+\makeatletter % wegen Laden aus normalem LaTeX-Dokument
+\@ifundefined{ifSERIF}{%
+   \newif\ifSERIF \SERIFfalse
+}{}
+
+\ifSERIF\else
   \RequirePackage[usefilenames,weight=Regular]{firamath-otf}
   \setmathfont[range=it]{texgyreheros-italic.otf}
   \setoperatorfont\mathsf
diff --git a/ptbposter/ptbposter-old-engines.clo b/ptbposter/ptbposter-old-engines.clo
index 3c0f16c2056cdc8419bc0693fd5e4617a35e9345..6121fb4b983ac640a39a1104af0f6a7c555c3de2 100644
--- a/ptbposter/ptbposter-old-engines.clo
+++ b/ptbposter/ptbposter-old-engines.clo
@@ -11,7 +11,12 @@
 \let\PTBdesignFont=\sffamily
 \RequirePackage[ttdefault=true,scale=1.034]{AnonymousPro}
 
-\ifPTB@serif
+\makeatletter % wegen Laden aus normalem LaTeX-Dokument
+\@ifundefined{ifSERIF}{%
+   \newif\ifSERIF \SERIFfalse
+}{}
+
+\ifSERIF
   \RequirePackage{qpxmath}
 \else
   %%%\renewcommand*\familydefault{\sfdefault} 
diff --git a/ptbposter/ptbposter-tcb.sty b/ptbposter/ptbposter-tcb.sty
index c092a53b36e10fc92fae9a4c9757383bd51f4c25..29ffe490b8a3a33684f745ae0e537089c5986dae 100644
--- a/ptbposter/ptbposter-tcb.sty
+++ b/ptbposter/ptbposter-tcb.sty
@@ -21,11 +21,11 @@
 
 \ifcase \PTB@boxlayout
     % 0
-  \g@addto@macro\PTB@boxesSet{enhanced jigsaw,sharp corners=downhill,}
+  \g@addto@macro\PTB@boxesSet{enhanced jigsaw,sharp corners=downhill,arc=.8ex}
 \or % 1
-  \g@addto@macro\PTB@boxesSet{enhanced jigsaw,sharp corners=uphill,}
+  \g@addto@macro\PTB@boxesSet{enhanced jigsaw,sharp corners=uphill,arc=.8ex}
 \or % 2
-  \g@addto@macro\PTB@boxesSet{enhanced jigsaw,}
+  \g@addto@macro\PTB@boxesSet{enhanced jigsaw,arc=.8ex}
 \or % 3
   \g@addto@macro\PTB@boxesSet{arc=0pt}
 \fi
diff --git a/ptbposter/ptbposter.cls b/ptbposter/ptbposter.cls
index 6b6cb8370c9fefd0d1692217dcc7f189de2e6e45..d08c21e353ca812bf6ca8f1226f2728a3ff02cd1 100644
--- a/ptbposter/ptbposter.cls
+++ b/ptbposter/ptbposter.cls
@@ -45,7 +45,7 @@
 
 \newif\ifPTBlandscape \PTBlandscapefalse
 \newif\ifPTB@XeOrLua \PTB@XeOrLuafalse
-\newif\ifPTB@serif \PTB@seriffalse
+\newif\ifSERIF \SERIFfalse
 \newif\ifPTB@logo@long@ \PTB@logo@long@true
 
 \RequirePackage{ifluatex,ifxetex}
@@ -68,10 +68,10 @@
 }
 
 \DeclareOption{sanserif}{% noch experimentell! Besser: LuaTeX/XeTeX + OTF
-  \PTB@seriffalse
+  \SERIFfalse
 }
 \DeclareOption{serif}{%
-  \PTB@seriftrue
+  \SERIFtrue
 }
 \DeclareOption{boldTitle}{%
   \global\let\PTB@title@series=\bfseries