--- /dev/null
+commit 40dd48d10911f4ff9b8dfbf16428fbc9acc434ba
+Author: Riza Sulistyo <trengginas@users.noreply.github.com>
+Date: Thu Jul 9 17:47:24 2020 +0700
+
+ Modify timer_id check on cancel() (#2463)
+
+ * modify timer_id check on cancel().
+
+ * modification based on comments.
+
+--- a/pjlib/include/pj/timer.h
++++ b/pjlib/include/pj/timer.h
+@@ -120,7 +120,10 @@ typedef struct pj_timer_entry
+
+ /**
+ * Internal unique timer ID, which is assigned by the timer heap.
+- * Application should not touch this ID.
++ * Positive values indicate that the timer entry is running,
++ * while -1 means that it's not. Any other value may indicate that it
++ * hasn't been properly initialised or is in a bad state.
++ * Application should not touch this ID.
+ */
+ pj_timer_id_t _timer_id;
+
+--- a/pjlib/src/pj/timer.c
++++ b/pjlib/src/pj/timer.c
+@@ -535,7 +535,7 @@ static int cancel( pj_timer_heap_t *ht,
+ PJ_CHECK_STACK();
+
+ // Check to see if the timer_id is out of range
+- if (entry->_timer_id < 0 || (pj_size_t)entry->_timer_id > ht->max_size) {
++ if (entry->_timer_id < 1 || (pj_size_t)entry->_timer_id >= ht->max_size) {
+ entry->_timer_id = -1;
+ return 0;
+ }