diff --git a/trunk/auto/depends.sh b/trunk/auto/depends.sh
index b0837dda2..215b86cae 100755
--- a/trunk/auto/depends.sh
+++ b/trunk/auto/depends.sh
@@ -384,6 +384,10 @@ fi
 if [[ $SRS_OSX == YES ]]; then
     _ST_MAKE=darwin-debug && _ST_EXTRA_CFLAGS="-DMD_HAVE_KQUEUE" && _ST_OBJ="DARWIN_`uname -r`_DBG"
 fi
+# For Ubuntu, the epoll detection might be fail.
+if [[ $OS_IS_UBUNTU == YES ]]; then
+    _ST_EXTRA_CFLAGS="$_ST_EXTRA_CFLAGS -DMD_HAVE_EPOLL"
+fi
 # Whether enable debug stats.
 if [[ $SRS_DEBUG_STATS == YES ]]; then
     _ST_EXTRA_CFLAGS="$_ST_EXTRA_CFLAGS -DDEBUG_STATS"
diff --git a/trunk/doc/CHANGELOG.md b/trunk/doc/CHANGELOG.md
index b4091386c..05badcfb9 100644
--- a/trunk/doc/CHANGELOG.md
+++ b/trunk/doc/CHANGELOG.md
@@ -8,6 +8,7 @@ The changelog for SRS.
 
 ## SRS 4.0 Changelog
 
+* v4.0, 2021-12-27, Fix [#2811](https://github.com/ossrs/srs/issues/2811): Fix ulimit issue by detecting epoll on Ubuntu. (#2811). v4.0.213
 * v4.0, 2021-12-26, Fix [#2247](https://github.com/ossrs/srs/pull/2247): Cleanup server for GMC, by WaitGroup to destroy. (#2247). v4.0.212
 * v4.0, 2021-12-25, For [#2809](https://github.com/ossrs/srs/issues/2809), HTTP: Fix 2GB+ mp4/flv file downloading error. (#2809)(#2780)(#2781). v4.0.211
 * v4.0, 2021-12-23, For [#2800](https://github.com/ossrs/srs/issues/2800), Fix bug for large mp4(5G+) offset. (#2800). v4.0.210
diff --git a/trunk/src/core/srs_core_version4.hpp b/trunk/src/core/srs_core_version4.hpp
index 44ff19545..ab1455f2a 100644
--- a/trunk/src/core/srs_core_version4.hpp
+++ b/trunk/src/core/srs_core_version4.hpp
@@ -9,6 +9,6 @@
 
 #define VERSION_MAJOR       4
 #define VERSION_MINOR       0
-#define VERSION_REVISION    212
+#define VERSION_REVISION    213
 
 #endif