diff --git a/telegram.spec b/telegram.spec
index 59b3b53..64b9557 100644
--- a/telegram.spec
+++ b/telegram.spec
@@ -3,7 +3,7 @@
 %define qt_majver %(echo %qt_ver | cut -d. -f1-2)
 
 Name:          telegram
-Version:       2.5.1
+Version:       2.5.7
 Release:       1mamba
 Summary:       The official desktop client for the Telegram messenger
 Group:         Graphical Desktop/Applications/Internet
@@ -64,7 +64,7 @@ BuildRequires: libz-devel
 #BuildRequires: libbreakpad-devel
 #BuildRequires: libunity-devel
 BuildRequires: range-v3-devel >= 0.11.0
-BuildRequires: libtg_owt-devel
+BuildRequires: libtg_owt-devel >= 0.0.20210128
 BuildRequires: libmicrosoft-gsl-devel
 BuildRequires: tl-expected-devel
 Requires:      kconfig
@@ -77,10 +77,8 @@ The official desktop client for the Telegram messenger.
 
 %prep
 %setup -q -n tdesktop-%{version}-full
-#-D -T
 
 %build
-#:<< _EOF
 %cmake -d build \
     -G Ninja \
     -DTDESKTOP_API_ID=17349 \
@@ -88,7 +86,7 @@ The official desktop client for the Telegram messenger.
     -DTDESKTOP_LAUNCHER_BASENAME="telegramdesktop" \
     -DDESKTOP_APP_SPECIAL_TARGET=""
 
-ninja
+ninja %{_smp_mflags}
 
 %install
 [ "%{buildroot}" != / ] && rm -rf "%{buildroot}"
@@ -124,6 +122,9 @@ fi
 %doc LICENSE LEGAL
 
 %changelog
+* Thu Jan 28 2021 Silvan Calarco <silvan.calarco@mambasoft.it> 2.5.7-1mamba
+- update to 2.5.7
+
 * Wed Dec 23 2020 Silvan Calarco <silvan.calarco@mambasoft.it> 2.5.1-1mamba
 - update to 2.5.1