diff --git a/TESTS/mbedmicro-rtos-mbed/MemoryPool/main.cpp b/TESTS/mbedmicro-rtos-mbed/MemoryPool/main.cpp
index 5c828277ce..58fdf1dbb8 100644
--- a/TESTS/mbedmicro-rtos-mbed/MemoryPool/main.cpp
+++ b/TESTS/mbedmicro-rtos-mbed/MemoryPool/main.cpp
@@ -23,10 +23,24 @@
 #error [NOT_SUPPORTED] MemoryPool test cases require a RTOS to run.
 #else
 
+#define TEST_ASSERT_DURATION_WITHIN(delta, expected, actual) \
+    do { \
+        using ct = std::common_type_t<decltype(delta), decltype(expected), decltype(actual)>; \
+        TEST_ASSERT_INT_WITHIN(ct(delta).count(), ct(expected).count(), ct(actual).count()); \
+    } while (0)
+
+#define TEST_ASSERT_TIME_POINT_WITHIN(delta, expected, actual) \
+    do { \
+        using ct_tp = std::common_type_t<decltype(expected), decltype(actual)>; \
+        using ct = std::common_type_t<decltype(delta), ct_tp::duration>; \
+        TEST_ASSERT_INT_WITHIN(ct(delta).count(), ct(expected.time_since_epoch()).count(), ct(actual.time_since_epoch()).count()); \
+    } while (0)
+
 using namespace utest::v1;
+using namespace std::chrono;
 
 #define THREAD_STACK_SIZE 512
-#define TEST_TIMEOUT 50
+#define TEST_TIMEOUT 50ms
 
 /* Enum used to select block allocation method. */
 typedef enum {
@@ -68,7 +82,7 @@ void comp_set(COMPLEX_TYPE *object, int a, char b, int c)
     object->c = c;
 }
 
-/* Template for functional tests for alloc(), calloc() functions
+/* Template for functional tests for try_alloc(), try_calloc() functions
  * of MemoryPool object.
  *
  * Given MemoryPool object of the specified type and queue size has
@@ -89,9 +103,9 @@ void test_mem_pool_alloc_success(AllocType atype)
     for (i = 0; i < numOfEntries; i++) {
         /* Allocate memory block. */
         if (atype == ALLOC) {
-            p_blocks[i] = mem_pool.alloc();
+            p_blocks[i] = mem_pool.try_alloc();
         } else {
-            p_blocks[i] = mem_pool.calloc();
+            p_blocks[i] = mem_pool.try_calloc();
         }
 
         /* Show that memory pool block has been allocated. */
@@ -112,7 +126,7 @@ void test_mem_pool_alloc_success(AllocType atype)
     }
 }
 
-/* Template for functional tests for alloc(), calloc() functions
+/* Template for functional tests for try_alloc(), try_calloc() functions
  * of MemoryPool object.
  *
  * Complex memory pool block type is used.
@@ -135,9 +149,9 @@ void test_mem_pool_alloc_success_complex(AllocType atype)
     for (i = 0; i < numOfEntries; i++) {
         /* Allocate memory block. */
         if (atype == ALLOC) {
-            p_blocks[i] = mem_pool.alloc();
+            p_blocks[i] = mem_pool.try_alloc();
         } else {
-            p_blocks[i] = mem_pool.calloc();
+            p_blocks[i] = mem_pool.try_calloc();
         }
 
         /* Show that memory pool block has been allocated. */
@@ -158,7 +172,7 @@ void test_mem_pool_alloc_success_complex(AllocType atype)
     }
 }
 
-/* Template for functional tests for alloc(), calloc() functions
+/* Template for functional tests for try_alloc(), try_calloc() functions
  * of MemoryPool object.
  *
  * Given MemoryPool has already max number of blocks allocated from the pool.
@@ -177,9 +191,9 @@ void test_mem_pool_alloc_fail(AllocType atype)
     /* Allocate all available blocks. */
     for (i = 0; i < numOfEntries; i++) {
         if (atype == ALLOC) {
-            p_blocks[i] = mem_pool.alloc();
+            p_blocks[i] = mem_pool.try_alloc();
         } else {
-            p_blocks[i] = mem_pool.calloc();
+            p_blocks[i] = mem_pool.try_calloc();
         }
 
         /* Show that memory pool block has been allocated. */
@@ -188,9 +202,9 @@ void test_mem_pool_alloc_fail(AllocType atype)
 
     /* There are no more blocks available. Try to allocate another block. */
     if (atype == ALLOC) {
-        p_extra_block = mem_pool.alloc();
+        p_extra_block = mem_pool.try_alloc();
     } else {
-        p_extra_block = mem_pool.calloc();
+        p_extra_block = mem_pool.try_calloc();
     }
 
     /* Show that memory pool block has NOT been allocated. */
@@ -216,9 +230,9 @@ void test_mem_pool_free_success(AllocType atype)
     /* Allocate all available blocks. */
     for (i = 0; i < numOfEntries; i++) {
         if (atype == ALLOC) {
-            p_blocks[i] = mem_pool.alloc();
+            p_blocks[i] = mem_pool.try_alloc();
         } else {
-            p_blocks[i] = mem_pool.calloc();
+            p_blocks[i] = mem_pool.try_calloc();
         }
 
         /* Show that memory pool block has been allocated. */
@@ -234,7 +248,7 @@ void test_mem_pool_free_success(AllocType atype)
     }
 }
 
-/* Template for functional tests for alloc(), calloc() functions
+/* Template for functional tests for try_alloc(), try_calloc() functions
  * of MemoryPool object.
  *
  * Basic memory pool block type is used.
@@ -256,9 +270,9 @@ void test_mem_pool_free_realloc_last(AllocType atype)
     /* Allocate all available blocks. */
     for (i = 0; i < numOfEntries; i++) {
         if (atype == ALLOC) {
-            p_blocks[i] = mem_pool.alloc();
+            p_blocks[i] = mem_pool.try_alloc();
         } else {
-            p_blocks[i] = mem_pool.calloc();
+            p_blocks[i] = mem_pool.try_calloc();
         }
 
         /* Init block. */
@@ -276,9 +290,9 @@ void test_mem_pool_free_realloc_last(AllocType atype)
 
     /* Try to allocate another block (one block is now available). */
     if (atype == ALLOC) {
-        p_blocks[numOfEntries - 1] = mem_pool.alloc();
+        p_blocks[numOfEntries - 1] = mem_pool.try_alloc();
     } else {
-        p_blocks[numOfEntries - 1] = mem_pool.calloc();
+        p_blocks[numOfEntries - 1] = mem_pool.try_calloc();
     }
 
     /* Show that memory pool block has been now allocated. */
@@ -290,7 +304,7 @@ void test_mem_pool_free_realloc_last(AllocType atype)
     }
 }
 
-/* Template for functional tests for alloc(), calloc() functions
+/* Template for functional tests for try_alloc(), try_calloc() functions
  * of MemoryPool object.
  *
  * Complex memory pool block type is used.
@@ -312,9 +326,9 @@ void test_mem_pool_free_realloc_last_complex(AllocType atype)
     /* Allocate all available blocks. */
     for (i = 0; i < numOfEntries; i++) {
         if (atype == ALLOC) {
-            p_blocks[i] = mem_pool.alloc();
+            p_blocks[i] = mem_pool.try_alloc();
         } else {
-            p_blocks[i] = mem_pool.calloc();
+            p_blocks[i] = mem_pool.try_calloc();
         }
 
         /* Init block. */
@@ -332,9 +346,9 @@ void test_mem_pool_free_realloc_last_complex(AllocType atype)
 
     /* Try to allocate another block (one block is now available). */
     if (atype == ALLOC) {
-        p_blocks[numOfEntries - 1] = mem_pool.alloc();
+        p_blocks[numOfEntries - 1] = mem_pool.try_alloc();
     } else {
-        p_blocks[numOfEntries - 1] = mem_pool.calloc();
+        p_blocks[numOfEntries - 1] = mem_pool.try_calloc();
     }
 
     /* Show that memory pool block has been now allocated. */
@@ -346,7 +360,7 @@ void test_mem_pool_free_realloc_last_complex(AllocType atype)
     }
 }
 
-/* Template for functional tests for alloc(), calloc() functions
+/* Template for functional tests for try_alloc(), try_calloc() functions
  * of MemoryPool object.
  *
  * Basic memory pool block type is used.
@@ -368,9 +382,9 @@ void test_mem_pool_free_realloc_first(AllocType atype)
     /* Allocate all available blocks. */
     for (i = 0; i < numOfEntries; i++) {
         if (atype == ALLOC) {
-            p_blocks[i] = mem_pool.alloc();
+            p_blocks[i] = mem_pool.try_alloc();
         } else {
-            p_blocks[i] = mem_pool.calloc();
+            p_blocks[i] = mem_pool.try_calloc();
         }
 
         /* Init block. */
@@ -388,9 +402,9 @@ void test_mem_pool_free_realloc_first(AllocType atype)
 
     /* Try to allocate another block (one block is now available). */
     if (atype == ALLOC) {
-        p_blocks[0] = mem_pool.alloc();
+        p_blocks[0] = mem_pool.try_alloc();
     } else {
-        p_blocks[0] = mem_pool.calloc();
+        p_blocks[0] = mem_pool.try_calloc();
     }
 
     /* Show that memory pool block has been now allocated. */
@@ -402,7 +416,7 @@ void test_mem_pool_free_realloc_first(AllocType atype)
     }
 }
 
-/* Template for functional tests for alloc(), calloc() functions
+/* Template for functional tests for try_alloc(), try_calloc() functions
  * of MemoryPool object.
  *
  * Complex memory pool block type is used.
@@ -424,9 +438,9 @@ void test_mem_pool_free_realloc_first_complex(AllocType atype)
     /* Allocate all available blocks. */
     for (i = 0; i < numOfEntries; i++) {
         if (atype == ALLOC) {
-            p_blocks[i] = mem_pool.alloc();
+            p_blocks[i] = mem_pool.try_alloc();
         } else {
-            p_blocks[i] = mem_pool.calloc();
+            p_blocks[i] = mem_pool.try_calloc();
         }
 
         /* Init block. */
@@ -444,9 +458,9 @@ void test_mem_pool_free_realloc_first_complex(AllocType atype)
 
     /* Try to allocate another block (one block is now available). */
     if (atype == ALLOC) {
-        p_blocks[0] = mem_pool.alloc();
+        p_blocks[0] = mem_pool.try_alloc();
     } else {
-        p_blocks[0] = mem_pool.calloc();
+        p_blocks[0] = mem_pool.try_calloc();
     }
 
     /* Show that memory pool block has been now allocated. */
@@ -458,7 +472,7 @@ void test_mem_pool_free_realloc_first_complex(AllocType atype)
     }
 }
 
-/* Test alloc timeout
+/* Test try_alloc_for/try_alloc_until timeout
  *
  * Given a pool with one slot for int data
  * When a thread tries to allocate two blocks with @ TEST_TIMEOUT timeout
@@ -471,18 +485,18 @@ void test_mem_pool_timeout()
     Timer timer;
     timer.start();
 
-    int *item = mem_pool.alloc_for(TEST_TIMEOUT);
+    int *item = mem_pool.try_alloc_for(TEST_TIMEOUT);
     TEST_ASSERT_NOT_NULL(item);
-    TEST_ASSERT_UINT32_WITHIN(TEST_TIMEOUT * 100, 0, timer.read_us());
+    TEST_ASSERT_DURATION_WITHIN(TEST_TIMEOUT / 10, 0ms, timer.elapsed_time());
 
-    item = mem_pool.alloc_for(TEST_TIMEOUT);
+    item = mem_pool.try_alloc_for(TEST_TIMEOUT);
     TEST_ASSERT_NULL(item);
-    TEST_ASSERT_UINT32_WITHIN(TEST_TIMEOUT * 100, TEST_TIMEOUT * 1000, timer.read_us());
+    TEST_ASSERT_DURATION_WITHIN(TEST_TIMEOUT / 10, TEST_TIMEOUT, timer.elapsed_time());
 
-    uint64_t end_time = Kernel::get_ms_count() + TEST_TIMEOUT;
-    item = mem_pool.alloc_until(end_time);
+    auto end_time = Kernel::Clock::now() + TEST_TIMEOUT;
+    item = mem_pool.try_alloc_until(end_time);
     TEST_ASSERT_NULL(item);
-    TEST_ASSERT_UINT64_WITHIN(TEST_TIMEOUT * 100, end_time, Kernel::get_ms_count());
+    TEST_ASSERT_TIME_POINT_WITHIN(TEST_TIMEOUT / 10, end_time, Kernel::Clock::now());
 }
 
 namespace {
@@ -516,18 +530,18 @@ void test_mem_pool_waitforever()
     Timer timer;
     timer.start();
 
-    int *item = pool.alloc_for(osWaitForever);
+    int *item = pool.try_alloc_for(Kernel::wait_for_u32_forever);
     TEST_ASSERT_NOT_NULL(item);
-    TEST_ASSERT_UINT32_WITHIN(TEST_TIMEOUT * 100, 0, timer.read_us());
+    TEST_ASSERT_DURATION_WITHIN(TEST_TIMEOUT / 10, 0ms, timer.elapsed_time());
 
     struct free_capture to_free;
     to_free.pool = &pool;
     to_free.item = item;
     t.start(callback(free_int_item, &to_free));
 
-    item = pool.alloc_for(osWaitForever);
+    item = pool.try_alloc_for(Kernel::wait_for_u32_forever);
     TEST_ASSERT_EQUAL(item, to_free.item);
-    TEST_ASSERT_UINT32_WITHIN(TEST_TIMEOUT * 100, TEST_TIMEOUT * 1000, timer.read_us());
+    TEST_ASSERT_DURATION_WITHIN(TEST_TIMEOUT / 10, TEST_TIMEOUT, timer.elapsed_time());
 
     t.join();
 }
@@ -632,12 +646,12 @@ void test_mem_pool_alloc_fail_wrapper()
 }
 
 Case cases[] = {
-    Case("Test: alloc()/calloc() - success, 4 bytes b_type, q_size equal to 1.", test_mem_pool_alloc_success_wrapper<int, 1>),
-    Case("Test: alloc()/calloc() - success, 4 bytes b_type, q_size equal to 3.", test_mem_pool_alloc_success_wrapper<int, 3>),
-    Case("Test: alloc()/calloc() - success, 1 bytes b_type, q_size equal to 1.", test_mem_pool_alloc_success_wrapper<char, 1>),
-    Case("Test: alloc()/calloc() - success, 1 bytes b_type, q_size equal to 3.", test_mem_pool_alloc_success_wrapper<char, 3>),
-    Case("Test: alloc()/calloc() - success, complex b_type, q_size equal to 1.", test_mem_pool_alloc_success_complex_wrapper<COMPLEX_TYPE, 1>),
-    Case("Test: alloc()/calloc() - success, complex b_type, q_size equal to 3.", test_mem_pool_alloc_success_complex_wrapper<COMPLEX_TYPE, 3>),
+    Case("Test: try_alloc()/try_calloc() - success, 4 bytes b_type, q_size equal to 1.", test_mem_pool_alloc_success_wrapper<int, 1>),
+    Case("Test: try_alloc()/try_calloc() - success, 4 bytes b_type, q_size equal to 3.", test_mem_pool_alloc_success_wrapper<int, 3>),
+    Case("Test: try_alloc()/try_calloc() - success, 1 bytes b_type, q_size equal to 1.", test_mem_pool_alloc_success_wrapper<char, 1>),
+    Case("Test: try_alloc()/try_calloc() - success, 1 bytes b_type, q_size equal to 3.", test_mem_pool_alloc_success_wrapper<char, 3>),
+    Case("Test: try_alloc()/try_calloc() - success, complex b_type, q_size equal to 1.", test_mem_pool_alloc_success_complex_wrapper<COMPLEX_TYPE, 1>),
+    Case("Test: try_alloc()/try_calloc() - success, complex b_type, q_size equal to 3.", test_mem_pool_alloc_success_complex_wrapper<COMPLEX_TYPE, 3>),
 
     Case("Test: free() - success, 4 bytes b_type, q_size equal to 1.", test_mem_pool_free_success_wrapper<int, 1>),
     Case("Test: free() - success, 4 bytes b_type, q_size equal to 3.", test_mem_pool_free_success_wrapper<int, 3>),
diff --git a/TESTS/mbedmicro-rtos-mbed/mail/main.cpp b/TESTS/mbedmicro-rtos-mbed/mail/main.cpp
index 5bf0bf3d6d..93719f4309 100644
--- a/TESTS/mbedmicro-rtos-mbed/mail/main.cpp
+++ b/TESTS/mbedmicro-rtos-mbed/mail/main.cpp
@@ -29,6 +29,13 @@
 #include "rtos.h"
 
 using namespace utest::v1;
+using namespace std::chrono;
+
+#define TEST_ASSERT_DURATION_WITHIN(delta, expected, actual) \
+    do { \
+        using ct = std::common_type_t<decltype(delta), decltype(expected), decltype(actual)>; \
+        TEST_ASSERT_INT_WITHIN(ct(delta).count(), ct(expected).count(), ct(actual).count()); \
+    } while (0)
 
 #if defined(__CORTEX_M23) || defined(__CORTEX_M33)
 #define THREAD_STACK_SIZE   512
@@ -43,9 +50,9 @@ using namespace utest::v1;
 #define THREAD_1_ID         1
 #define THREAD_2_ID         2
 #define THREAD_3_ID         3
-#define QUEUE_PUT_DELAY_1   5
-#define QUEUE_PUT_DELAY_2   50
-#define QUEUE_PUT_DELAY_3   100
+#define QUEUE_PUT_DELAY_1   5ms
+#define QUEUE_PUT_DELAY_2   50ms
+#define QUEUE_PUT_DELAY_3   100ms
 #define DATA_BASE           100
 
 
@@ -55,27 +62,26 @@ typedef struct {
 } mail_t;
 
 
-template<uint8_t thread_id, uint32_t wait_ms, uint32_t send_count>
-void send_thread(Mail<mail_t, QUEUE_SIZE> *m)
+void send_thread(Mail<mail_t, QUEUE_SIZE> *m, uint8_t thread_id, milliseconds wait, uint32_t send_count)
 {
     uint32_t data = thread_id * DATA_BASE;
 
     for (uint32_t i = 0; i < send_count; i++) {
-        mail_t *mail = m->alloc();
+        mail_t *mail = m->try_alloc();
         mail->thread_id = thread_id;
         mail->data = data++;
         m->put(mail);
-        ThisThread::sleep_for(wait_ms);
+        ThisThread::sleep_for(wait);
     }
 }
 
-template<uint8_t thread_id, uint32_t queue_size, uint32_t wait_ms>
-void receive_thread(Mail<mail_t, queue_size> *m)
+template<uint32_t queue_size>
+void receive_thread(Mail<mail_t, queue_size> *m, uint8_t thread_id, milliseconds wait)
 {
     int result_counter = 0;
     uint32_t data = thread_id * DATA_BASE;
 
-    ThisThread::sleep_for(wait_ms);
+    ThisThread::sleep_for(wait);
     for (uint32_t i = 0; i < queue_size; i++) {
         osEvent evt = m->get();
         if (evt.status == osEventMail) {
@@ -108,10 +114,10 @@ void test_single_thread_order(void)
 
     // mail send thread creation
     Thread thread(osPriorityNormal, THREAD_STACK_SIZE);
-    thread.start(callback(send_thread<THREAD_1_ID, QUEUE_PUT_DELAY_1, QUEUE_SIZE>, &mail_box));
+    thread.start([&] { send_thread(&mail_box, THREAD_1_ID, QUEUE_PUT_DELAY_1, QUEUE_SIZE); });
 
     // wait for some mail to be collected
-    ThisThread::sleep_for(10);
+    ThisThread::sleep_for(10ms);
 
     for (uint32_t i = 0; i < QUEUE_SIZE; i++) {
         // mail receive (main thread)
@@ -148,12 +154,12 @@ void test_multi_thread_order(void)
     Thread thread1(osPriorityNormal, THREAD_STACK_SIZE);
     Thread thread2(osPriorityNormal, THREAD_STACK_SIZE);
     Thread thread3(osPriorityNormal, THREAD_STACK_SIZE);
-    thread1.start(callback(send_thread<THREAD_1_ID, QUEUE_PUT_DELAY_1, 7>, &mail_box));
-    thread2.start(callback(send_thread<THREAD_2_ID, QUEUE_PUT_DELAY_2, 5>, &mail_box));
-    thread3.start(callback(send_thread<THREAD_3_ID, QUEUE_PUT_DELAY_3, 4>, &mail_box));
+    thread1.start([&] { send_thread(&mail_box, THREAD_1_ID, QUEUE_PUT_DELAY_1, 7); });
+    thread2.start([&] { send_thread(&mail_box, THREAD_2_ID, QUEUE_PUT_DELAY_2, 5); });
+    thread3.start([&] { send_thread(&mail_box, THREAD_3_ID, QUEUE_PUT_DELAY_3, 4); });
 
     // wait for some mail to be collected
-    ThisThread::sleep_for(10);
+    ThisThread::sleep_for(10ms);
 
     for (uint32_t i = 0; i < QUEUE_SIZE; i++) {
         // mail receive (main thread)
@@ -191,30 +197,30 @@ void test_multi_thread_multi_mail_order(void)
     Thread thread1(osPriorityNormal, THREAD_STACK_SIZE);
     Thread thread2(osPriorityNormal, THREAD_STACK_SIZE);
     Thread thread3(osPriorityNormal, THREAD_STACK_SIZE);
-    thread1.start(callback(receive_thread<THREAD_1_ID, 4, 0>, mail_box + 1));
-    thread2.start(callback(receive_thread<THREAD_2_ID, 4, 10>, mail_box + 2));
-    thread3.start(callback(receive_thread<THREAD_3_ID, 4, 100>, mail_box + 3));
+    thread1.start([&] { receive_thread<4>(mail_box + 1, THREAD_1_ID, 0ms); });
+    thread2.start([&] { receive_thread<4>(mail_box + 2, THREAD_2_ID, 10ms); });
+    thread3.start([&] { receive_thread<4>(mail_box + 3, THREAD_3_ID, 100ms); });
 
     for (uint32_t i = 0; i < 4; i++) {
         id = THREAD_1_ID;
-        mail = mail_box[id].alloc();
+        mail = mail_box[id].try_alloc();
         mail->thread_id = id;
         mail->data = data[id]++;
         mail_box[id].put(mail);
 
         id = THREAD_2_ID;
-        mail = mail_box[id].alloc();
+        mail = mail_box[id].try_alloc();
         mail->thread_id = id;
         mail->data = data[id]++;
         mail_box[id].put(mail);
 
         id = THREAD_3_ID;
-        mail = mail_box[id].alloc();
+        mail = mail_box[id].try_alloc();
         mail->thread_id = id;
         mail->data = data[id]++;
         mail_box[id].put(mail);
 
-        ThisThread::sleep_for(i * 10);
+        ThisThread::sleep_for(i * 10ms);
     }
 
     thread1.join();
@@ -238,7 +244,7 @@ void test_free_wrong()
     status = mail_box.free(mail);
     TEST_ASSERT_EQUAL(osErrorParameter, status);
 
-    mail = mail_box.alloc();
+    mail = mail_box.try_alloc();
     TEST_ASSERT_NOT_EQUAL(NULL, mail);
 
     mail = &data;
@@ -262,7 +268,7 @@ void test_free_null()
     status = mail_box.free(mail);
     TEST_ASSERT_EQUAL(osErrorParameter, status);
 
-    mail = mail_box.alloc();
+    mail = mail_box.try_alloc();
     TEST_ASSERT_NOT_EQUAL(NULL, mail);
 
     mail = NULL;
@@ -282,8 +288,8 @@ void test_get_empty_timeout()
     Timer timer;
 
     timer.start();
-    osEvent evt = mail_box.get(50);
-    TEST_ASSERT_UINT32_WITHIN(5000, 50000, timer.read_us());
+    osEvent evt = mail_box.get(50ms);
+    TEST_ASSERT_DURATION_WITHIN(5ms, 50ms, timer.elapsed_time());
     TEST_ASSERT_EQUAL(osEventTimeout, evt.status);
 }
 
@@ -297,7 +303,7 @@ void test_get_empty_no_timeout()
 {
     Mail<uint32_t, 4> mail_box;
 
-    osEvent evt = mail_box.get(0);
+    osEvent evt = mail_box.get(0ms);
     TEST_ASSERT_EQUAL(osOK, evt.status);
 }
 
@@ -316,14 +322,14 @@ void test_order(void)
     const int32_t TEST_VAL1 = 123;
     const int32_t TEST_VAL2 = 456;
 
-    int32_t *mail1 = mail_box.alloc();
+    int32_t *mail1 = mail_box.try_alloc();
     TEST_ASSERT_NOT_EQUAL(NULL, mail1);
 
     *mail1 = TEST_VAL1;
     status = mail_box.put(mail1);
     TEST_ASSERT_EQUAL(osOK, status);
 
-    int32_t *mail2 = mail_box.alloc();
+    int32_t *mail2 = mail_box.try_alloc();
     TEST_ASSERT_NOT_EQUAL(NULL, mail2);
 
     *mail2 = TEST_VAL2;
@@ -354,9 +360,9 @@ void test_order(void)
 /** Test Mail box max size limit
 
     Given an Mail box with max size of 4 elements
-    When call @a alloc four times it returns memory blocks
+    When call @a try_alloc four times it returns memory blocks
     Then the memory blocks should be valid
-    When call @a alloc one more time it returns memory blocks
+    When call @a try_alloc one more time it returns memory blocks
     Then the memory blocks should be not valid (NULL - no memory available)
  */
 void test_max_size()
@@ -366,23 +372,23 @@ void test_max_size()
     const uint32_t TEST_VAL = 123;
 
     // 1 OK
-    uint32_t *mail1 = mail_box.alloc();
+    uint32_t *mail1 = mail_box.try_alloc();
     TEST_ASSERT_NOT_EQUAL(NULL, mail1);
 
     // 2 OK
-    uint32_t *mail2 = mail_box.alloc();
+    uint32_t *mail2 = mail_box.try_alloc();
     TEST_ASSERT_NOT_EQUAL(NULL, mail2);
 
     // 3 OK
-    uint32_t *mail3 = mail_box.alloc();
+    uint32_t *mail3 = mail_box.try_alloc();
     TEST_ASSERT_NOT_EQUAL(NULL, mail3);
 
     // 4 OK
-    uint32_t *mail4 = mail_box.alloc();
+    uint32_t *mail4 = mail_box.try_alloc();
     TEST_ASSERT_NOT_EQUAL(NULL, mail4);
 
     // 5 KO
-    uint32_t *mail5 = mail_box.alloc();
+    uint32_t *mail5 = mail_box.try_alloc();
     TEST_ASSERT_EQUAL(NULL, mail5);
 
 
@@ -412,7 +418,7 @@ void test_data_type(void)
     Mail<T, 4> mail_box;
     const T TEST_VAL = 123;
 
-    T *mail = mail_box.alloc();
+    T *mail = mail_box.try_alloc();
     TEST_ASSERT_NOT_EQUAL(NULL, mail);
 
     *mail = TEST_VAL;
@@ -430,17 +436,17 @@ void test_data_type(void)
     TEST_ASSERT_EQUAL(osOK, status);
 }
 
-/** Test calloc - memory block allocation with resetting
+/** Test try_calloc - memory block allocation with resetting
 
     Given an empty Mail box
-    When call @a calloc it returns allocated memory block
+    When call @a try_calloc it returns allocated memory block
     Then the memory block should be valid and filled with zeros
  */
 void test_calloc()
 {
     Mail<uint32_t, 1> mail_box;
 
-    uint32_t *mail = mail_box.calloc();
+    uint32_t *mail = mail_box.try_calloc();
     TEST_ASSERT_NOT_EQUAL(NULL, mail);
     TEST_ASSERT_EQUAL(0, *mail);
 }
@@ -455,7 +461,7 @@ void test_mail_empty()
 {
     Mail<mail_t, 1> m;
 
-    mail_t *mail = m.alloc();
+    mail_t *mail = m.try_alloc();
 
     TEST_ASSERT_EQUAL(true,  m.empty());
 
@@ -474,7 +480,7 @@ void test_mail_full()
 {
     Mail<mail_t, 1> m;
 
-    mail_t *mail = m.alloc();
+    mail_t *mail = m.try_alloc();
 
     TEST_ASSERT_EQUAL(false,  m.full());
 
@@ -490,7 +496,7 @@ utest::v1::status_t test_setup(const size_t number_of_cases)
 }
 
 Case cases[] = {
-    Case("Test calloc", test_calloc),
+    Case("Test try_calloc", test_calloc),
     Case("Test message type uint8", test_data_type<uint8_t>),
     Case("Test message type uint16", test_data_type<uint16_t>),
     Case("Test message type uint32", test_data_type<uint32_t>),
diff --git a/rtos/Mail.h b/rtos/Mail.h
index af9ce312e7..feca403fdb 100644
--- a/rtos/Mail.h
+++ b/rtos/Mail.h
@@ -105,11 +105,25 @@ public:
      * @return  Pointer to memory block that you can fill with mail or nullptr in case error.
      *
      * @note You may call this function from ISR context.
-     * @note If blocking is required, use Mail::alloc_for or Mail::alloc_until
+     * @note If blocking is required, use Mail::try_alloc_for or Mail::try_alloc_until
+     * @deprecated Replaced with try_alloc. In future alloc() will be an untimed blocking call.
      */
+    MBED_DEPRECATED_SINCE("mbed-os-6.0.0", "Replaced with try_alloc. In future alloc() will be an untimed blocking call.")
     T *alloc(MBED_UNUSED uint32_t millisec = 0)
     {
-        return _pool.alloc();
+        return try_alloc();
+    }
+
+    /** Allocate a memory block of type T, without blocking.
+     *
+     * @return  Pointer to memory block that you can fill with mail or nullptr in case error.
+     *
+     * @note You may call this function from ISR context.
+     * @note If blocking is required, use Mail::try_alloc_for or Mail::try_alloc_until
+     */
+    T *try_alloc()
+    {
+        return _pool.try_alloc();
     }
 
     /** Allocate a memory block of type T, optionally blocking.
@@ -120,9 +134,9 @@ public:
      *
      * @note You may call this function from ISR context if the millisec parameter is set to 0.
      */
-    T *alloc_for(Kernel::Clock::duration_u32 rel_time)
+    T *try_alloc_for(Kernel::Clock::duration_u32 rel_time)
     {
-        return _pool.alloc_for(rel_time);
+        return _pool.try_alloc_for(rel_time);
     }
 
     /** Allocate a memory block of type T, optionally blocking.
@@ -137,7 +151,7 @@ public:
     MBED_DEPRECATED_SINCE("mbed-os-6.0.0", "Pass a chrono duration, not an integer millisecond count. For example use `5s` rather than `5000`.")
     T *alloc_for(uint32_t millisec)
     {
-        return alloc_for(std::chrono::duration<uint32_t, std::milli>(millisec));
+        return try_alloc_for(std::chrono::duration<uint32_t, std::milli>(millisec));
     }
 
     /** Allocate a memory block of type T, blocking.
@@ -152,9 +166,9 @@ public:
      *   wait is <= 0x7fffffff milliseconds (~24 days). If the limit is exceeded,
      *   the wait will time out earlier than specified.
      */
-    T *alloc_until(Kernel::Clock::time_point abs_time)
+    T *try_alloc_until(Kernel::Clock::time_point abs_time)
     {
-        return _pool.alloc_until(abs_time);
+        return _pool.try_alloc_until(abs_time);
     }
 
     /** Allocate a memory block of type T, blocking.
@@ -174,7 +188,7 @@ public:
     MBED_DEPRECATED_SINCE("mbed-os-6.0.0", "Pass a chrono time_point, not an integer millisecond count. For example use `Kernel::Clock::now() + 5s` rather than `Kernel::get_ms_count() + 5000`.")
     T *alloc_until(uint64_t millisec)
     {
-        return alloc_until(Kernel::Clock::time_point(std::chrono::duration<uint64_t, std::milli>(millisec)));
+        return try_alloc_until(Kernel::Clock::time_point(std::chrono::duration<uint64_t, std::milli>(millisec)));
     }
 
     /** Allocate a memory block of type T, and set memory block to zero.
@@ -183,12 +197,26 @@ public:
      *
      * @return  Pointer to memory block that you can fill with mail or nullptr in case error.
      *
-     * @note You may call this function from ISR context if the millisec parameter is set to 0.
-     * @note If blocking is required, use Mail::calloc_for or Mail::calloc_until
+     * @note You may call this function from ISR context.
+     * @note If blocking is required, use Mail::try_calloc_for or Mail::try_calloc_until
+     * @deprecated Replaced with try_calloc. In future calloc() will be an untimed blocking call.
      */
+    MBED_DEPRECATED_SINCE("mbed-os-6.0.0", "Replaced with try_calloc. In future calloc() will be an untimed blocking call.")
     T *calloc(MBED_UNUSED uint32_t millisec = 0)
     {
-        return _pool.calloc();
+        return try_calloc();
+    }
+
+    /** Allocate a memory block of type T, and set memory block to zero.
+     *
+     * @return  Pointer to memory block that you can fill with mail or nullptr in case error.
+     *
+     * @note You may call this function from ISR context.
+     * @note If blocking is required, use Mail::try_calloc_for or Mail::try_calloc_until
+     */
+    T *try_calloc()
+    {
+        return _pool.try_calloc();
     }
 
     /** Allocate a memory block of type T, optionally blocking, and set memory block to zero.
@@ -199,9 +227,9 @@ public:
      *
      * @note You may call this function from ISR context if the rel_time parameter is set to 0.
      */
-    T *calloc_for(Kernel::Clock::duration_u32 rel_time)
+    T *try_calloc_for(Kernel::Clock::duration_u32 rel_time)
     {
-        return _pool.alloc_for(rel_time);
+        return _pool.try_calloc_for(rel_time);
     }
 
     /** Allocate a memory block of type T, optionally blocking, and set memory block to zero.
@@ -216,7 +244,7 @@ public:
     MBED_DEPRECATED_SINCE("mbed-os-6.0.0", "Pass a chrono duration, not an integer millisecond count. For example use `5s` rather than `5000`.")
     T *calloc_for(uint32_t millisec)
     {
-        return calloc_for(std::chrono::duration<uint32_t, std::milli>(millisec));
+        return try_calloc_for(std::chrono::duration<uint32_t, std::milli>(millisec));
     }
 
     /** Allocate a memory block of type T, blocking, and set memory block to zero.
@@ -231,9 +259,9 @@ public:
      *   wait is <= 0x7fffffff milliseconds (~24 days). If the limit is exceeded,
      *   the wait will time out earlier than specified.
      */
-    T *calloc_until(Kernel::Clock::time_point abs_time)
+    T *try_calloc_until(Kernel::Clock::time_point abs_time)
     {
-        return _pool.calloc_until(abs_time);
+        return _pool.try_calloc_until(abs_time);
     }
 
     /** Allocate a memory block of type T, blocking, and set memory block to zero.
@@ -253,7 +281,7 @@ public:
     MBED_DEPRECATED_SINCE("mbed-os-6.0.0", "Pass a chrono time_point, not an integer millisecond count. For example use `Kernel::Clock::now() + 5s` rather than `Kernel::get_ms_count() + 5000`.")
     T *calloc_until(uint64_t millisec)
     {
-        return calloc_until(Kernel::Clock::time_point(std::chrono::duration<uint64_t, std::milli>(millisec)));
+        return try_calloc_until(Kernel::Clock::time_point(std::chrono::duration<uint64_t, std::milli>(millisec)));
     }
 
     /** Put a mail in the queue.
diff --git a/rtos/MemoryPool.h b/rtos/MemoryPool.h
index 81456eddd6..9b247d1962 100644
--- a/rtos/MemoryPool.h
+++ b/rtos/MemoryPool.h
@@ -88,10 +88,12 @@ public:
       @return  address of the allocated memory block or nullptr in case of no memory available.
 
       @note You may call this function from ISR context.
+      @deprecated Replaced with try_alloc. In future alloc() will be an untimed blocking call.
     */
-    T *alloc(void)
+    MBED_DEPRECATED_SINCE("mbed-os-6.0.0", "Replaced with try_alloc. In future alloc() will be an untimed blocking call.")
+    T *alloc()
     {
-        return (T *)osMemoryPoolAlloc(_id, 0);
+        return try_alloc();
     }
 
     /** Allocate a memory block from a memory pool, without blocking.
@@ -99,7 +101,7 @@ public:
 
       @note You may call this function from ISR context.
     */
-    T *try_alloc(void)
+    T *try_alloc()
     {
         return (T *)osMemoryPoolAlloc(_id, 0);
     }
@@ -123,7 +125,7 @@ public:
 
       @note You may call this function from ISR context if the rel_time parameter is set to 0.
     */
-    T *alloc_for(Kernel::Clock::duration_u32 rel_time)
+    T *try_alloc_for(Kernel::Clock::duration_u32 rel_time)
     {
         return (T *)osMemoryPoolAlloc(_id, rel_time.count());
     }
@@ -156,7 +158,7 @@ public:
         wait is <= 0x7fffffff milliseconds (~24 days). If the limit is exceeded,
         the wait will time out earlier than specified.
     */
-    T *alloc_until(Kernel::Clock::time_point abs_time)
+    T *try_alloc_until(Kernel::Clock::time_point abs_time)
     {
         Kernel::Clock::time_point now = Kernel::Clock::now();
         Kernel::Clock::duration_u32 rel_time;
@@ -167,16 +169,28 @@ public:
         } else {
             rel_time = abs_time - now;
         }
-        return alloc_for(rel_time);
+        return try_alloc_for(rel_time);
     }
     /** Allocate a memory block from a memory pool, without blocking, and set memory block to zero.
       @return  address of the allocated memory block or nullptr in case of no memory available.
 
       @note You may call this function from ISR context.
+      @deprecated Replaced with try_calloc. In future calloc() will be an untimed blocking call.
     */
-    T *calloc(void)
+    MBED_DEPRECATED_SINCE("mbed-os-6.0.0", "Replaced with try_calloc. In future calloc() will be an untimed blocking call.")
+    T *calloc()
     {
-        T *item = alloc();
+        return try_calloc();
+    }
+
+    /** Allocate a memory block from a memory pool, without blocking, and set memory block to zero.
+      @return  address of the allocated memory block or nullptr in case of no memory available.
+
+      @note You may call this function from ISR context.
+    */
+    T *try_calloc()
+    {
+        T *item = try_alloc();
         if (item != nullptr) {
             memset(item, 0, sizeof(T));
         }
@@ -202,7 +216,7 @@ public:
 
       @note You may call this function from ISR context if the rel_time parameter is set to 0.
     */
-    T *calloc_for(Kernel::Clock::duration_u32 rel_time)
+    T *try_calloc_for(Kernel::Clock::duration_u32 rel_time)
     {
         T *item = alloc_for(rel_time);
         if (item != nullptr) {
@@ -239,7 +253,7 @@ public:
         wait is <= 0x7fffffff milliseconds (~24 days). If the limit is exceeded,
         the wait will time out earlier than specified.
     */
-    T *calloc_until(Kernel::Clock::time_point abs_time)
+    T *try_calloc_until(Kernel::Clock::time_point abs_time)
     {
         T *item = alloc_until(abs_time);
         if (item != nullptr) {