diff --git a/ChangeLog.d/issue4286.txt b/ChangeLog.d/issue4286.txt
new file mode 100644
index 0000000..3fb9585
--- /dev/null
+++ b/ChangeLog.d/issue4286.txt
@@ -0,0 +1,9 @@
+Removals
+   * Remove the following deprecated library constants
+     MBEDTLS_SSL_PROTO_TLS1, MBEDTLS_SSL_PROTO_TLS1_1,
+     MBEDTLS_SSL_CBC_RECORD_SPLITTING,
+     MBEDTLS_SSL_CBC_RECORD_SPLITTING_ENABLED,
+     MBEDTLS_SSL_CBC_RECORD_SPLITTING_DISABLED and functions
+     ssl_write_split(), mbedtls_ssl_conf_cbc_record_splitting() as well as test
+     function component_test_variable_ssl_in_out_buffer_len_record_splitting().
+     Fixes #4286.
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 4905b92..993b90f 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -1593,18 +1593,6 @@
 #define MBEDTLS_SSL_KEEP_PEER_CERTIFICATE
 
 /**
- * \def MBEDTLS_SSL_CBC_RECORD_SPLITTING
- *
- * Enable 1/n-1 record splitting for CBC mode in TLS.
- *
- * This is a countermeasure to the BEAST attack, which also minimizes the risk
- * of interoperability issues compared to sending 0-length records.
- *
- * Comment this macro to disable 1/n-1 record splitting.
- */
-#define MBEDTLS_SSL_CBC_RECORD_SPLITTING
-
-/**
  * \def MBEDTLS_SSL_RENEGOTIATION
  *
  * Enable support for TLS renegotiation.
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 39661cb..b520042 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -198,9 +198,6 @@
 #define MBEDTLS_SSL_SESSION_TICKETS_DISABLED     0
 #define MBEDTLS_SSL_SESSION_TICKETS_ENABLED      1
 
-#define MBEDTLS_SSL_CBC_RECORD_SPLITTING_DISABLED    0
-#define MBEDTLS_SSL_CBC_RECORD_SPLITTING_ENABLED     1
-
 #define MBEDTLS_SSL_PRESET_DEFAULT              0
 #define MBEDTLS_SSL_PRESET_SUITEB               2
 
@@ -1192,9 +1189,6 @@
 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
     unsigned int anti_replay : 1;   /*!< detect and prevent replay?         */
 #endif
-#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
-    unsigned int cbc_record_splitting : 1;  /*!< do cbc record splitting    */
-#endif
 #if defined(MBEDTLS_SSL_RENEGOTIATION)
     unsigned int disable_renegotiation : 1; /*!< disable renegotiation?     */
 #endif
@@ -1356,10 +1350,6 @@
     uint16_t mtu;               /*!< path mtu, used to fragment outgoing messages */
 #endif /* MBEDTLS_SSL_PROTO_DTLS */
 
-#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
-    signed char split_done;     /*!< current record already splitted? */
-#endif /* MBEDTLS_SSL_CBC_RECORD_SPLITTING */
-
     /*
      * PKI layer
      */
diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index 540d5d1..081a0b2 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -5476,44 +5476,6 @@
 }
 
 /*
- * Write application data, doing 1/n-1 splitting if necessary.
- *
- * With non-blocking I/O, ssl_write_real() may return WANT_WRITE,
- * then the caller will call us again with the same arguments, so
- * remember whether we already did the split or not.
- */
-#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
-static int ssl_write_split( mbedtls_ssl_context *ssl,
-                            const unsigned char *buf, size_t len )
-{
-    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-
-    if( ssl->conf->cbc_record_splitting ==
-            MBEDTLS_SSL_CBC_RECORD_SPLITTING_DISABLED ||
-        len <= 1 ||
-        ssl->minor_ver > MBEDTLS_SSL_MINOR_VERSION_1 ||
-        mbedtls_cipher_get_cipher_mode( &ssl->transform_out->cipher_ctx_enc )
-                                != MBEDTLS_MODE_CBC )
-    {
-        return( ssl_write_real( ssl, buf, len ) );
-    }
-
-    if( ssl->split_done == 0 )
-    {
-        if( ( ret = ssl_write_real( ssl, buf, 1 ) ) <= 0 )
-            return( ret );
-        ssl->split_done = 1;
-    }
-
-    if( ( ret = ssl_write_real( ssl, buf + 1, len - 1 ) ) <= 0 )
-        return( ret );
-    ssl->split_done = 0;
-
-    return( ret + 1 );
-}
-#endif /* MBEDTLS_SSL_CBC_RECORD_SPLITTING */
-
-/*
  * Write application data (public-facing wrapper)
  */
 int mbedtls_ssl_write( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len )
@@ -5542,11 +5504,7 @@
         }
     }
 
-#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
-    ret = ssl_write_split( ssl, buf, len );
-#else
     ret = ssl_write_real( ssl, buf, len );
-#endif
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write" ) );
 
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 58675db..771e01a 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -3307,10 +3307,6 @@
     ssl->out_msgtype = 0;
     ssl->out_msglen = 0;
     ssl->out_left = 0;
-#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
-    if( ssl->split_done != MBEDTLS_SSL_CBC_RECORD_SPLITTING_DISABLED )
-        ssl->split_done = 0;
-#endif
 
     memset( ssl->cur_out_ctr, 0, sizeof( ssl->cur_out_ctr ) );
 
@@ -4202,13 +4198,6 @@
 }
 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
 
-#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
-void mbedtls_ssl_conf_cbc_record_splitting( mbedtls_ssl_config *conf, char split )
-{
-    conf->cbc_record_splitting = split;
-}
-#endif
-
 void mbedtls_ssl_conf_legacy_renegotiation( mbedtls_ssl_config *conf, int allow_legacy )
 {
     conf->allow_legacy_renegotiation = allow_legacy;
@@ -6234,10 +6223,6 @@
     conf->extended_ms = MBEDTLS_SSL_EXTENDED_MS_ENABLED;
 #endif
 
-#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
-    conf->cbc_record_splitting = MBEDTLS_SSL_CBC_RECORD_SPLITTING_ENABLED;
-#endif
-
 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) && defined(MBEDTLS_SSL_SRV_C)
     conf->f_cookie_write = ssl_cookie_write_dummy;
     conf->f_cookie_check = ssl_cookie_check_dummy;
diff --git a/programs/fuzz/fuzz_client.c b/programs/fuzz/fuzz_client.c
index 618eda2..a637173 100644
--- a/programs/fuzz/fuzz_client.c
+++ b/programs/fuzz/fuzz_client.c
@@ -109,9 +109,6 @@
 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
     mbedtls_ssl_conf_encrypt_then_mac( &conf, (options & 0x20) ? MBEDTLS_SSL_ETM_DISABLED : MBEDTLS_SSL_ETM_ENABLED);
 #endif
-#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
-    mbedtls_ssl_conf_cbc_record_splitting( &conf, (options & 0x40) ? MBEDTLS_SSL_CBC_RECORD_SPLITTING_ENABLED : MBEDTLS_SSL_CBC_RECORD_SPLITTING_DISABLED );
-#endif
 #if defined(MBEDTLS_SSL_RENEGOTIATION)
     mbedtls_ssl_conf_renegotiation( &conf, (options & 0x80) ? MBEDTLS_SSL_RENEGOTIATION_ENABLED : MBEDTLS_SSL_RENEGOTIATION_DISABLED );
 #endif
diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index fb3cce1..a643900 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -248,13 +248,6 @@
 #define USAGE_MAX_FRAG_LEN ""
 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
 
-#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
-#define USAGE_RECSPLIT \
-    "    recsplit=0/1        default: (library default: on)\n"
-#else
-#define USAGE_RECSPLIT
-#endif
-
 #if defined(MBEDTLS_DHM_C)
 #define USAGE_DHMLEN \
     "    dhmlen=%%d           default: (library default: 1024 bits)\n"
@@ -414,7 +407,6 @@
     USAGE_ETM                                               \
     USAGE_REPRODUCIBLE                                      \
     USAGE_CURVES                                            \
-    USAGE_RECSPLIT                                          \
     USAGE_DHMLEN                                            \
     "\n"
 #define USAGE4 \
@@ -1780,13 +1772,6 @@
 #endif /* MBEDTLS_SSL_DTLS_SRTP */
 #endif /* MBEDTLS_SSL_EXPORT_KEYS */
 
-#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
-    if( opt.recsplit != DFL_RECSPLIT )
-        mbedtls_ssl_conf_cbc_record_splitting( &conf, opt.recsplit
-                                  ? MBEDTLS_SSL_CBC_RECORD_SPLITTING_ENABLED
-                                  : MBEDTLS_SSL_CBC_RECORD_SPLITTING_DISABLED );
-#endif
-
 #if defined(MBEDTLS_DHM_C)
     if( opt.dhmlen != DFL_DHMLEN )
         mbedtls_ssl_conf_dhm_min_bitlen( &conf, opt.dhmlen );
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 1653ad8..ef2b636 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -2043,24 +2043,6 @@
     if_build_succeeded tests/compat.sh
 }
 
-component_test_variable_ssl_in_out_buffer_len_record_splitting () {
-    msg "build: MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH and MBEDTLS_SSL_CBC_RECORD_SPLITTING enabled (ASan build)"
-    scripts/config.py set MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH
-    scripts/config.py set MBEDTLS_SSL_CBC_RECORD_SPLITTING
-
-    CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan .
-    make
-
-    msg "test: MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH and MBEDTLS_SSL_CBC_RECORD_SPLITTING"
-    make test
-
-    msg "test: ssl-opt.sh, MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH and MBEDTLS_SSL_CBC_RECORD_SPLITTING enabled"
-    if_build_succeeded tests/ssl-opt.sh
-
-    msg "test: compat.sh, MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH and MBEDTLS_SSL_CBC_RECORD_SPLITTING enabled"
-    if_build_succeeded tests/compat.sh
-}
-
 component_test_ssl_alloc_buffer_and_mfl () {
     msg "build: default config with memory buffer allocator and MFL extension"
     scripts/config.py set MBEDTLS_MEMORY_BUFFER_ALLOC_C