in fact some of them were inherited from earlier versions.
-----------------------------------------------------------------------------------------
-accept_8bitmime boolean true main 1.60 changed to true in 4.78
+accept_8bitmime boolean true main 1.60 changed to true in 4.80
acl_not_smtp string* unset main 4.11
acl_not_smtp_mime string* unset main 4.51 with content scan
acl_smtp_auth string* unset main 4.00
acl_smtp_connect string* unset main 4.11
acl_smtp_data string* unset main 4.00
+acl_smtp_data_prdr string* unset main 4.82 with experimental_prdr, 4.83 unless disable_prdr
+acl_smtp_dkim string* unset main 4.70 unless disable_dkim
acl_smtp_etrn string* unset main 4.00
acl_smtp_expn string* unset main 4.00
acl_smtp_helo string* unset main 4.20
allow_mx_to_ip boolean false main 3.14
allow_symlink boolean false appendfile
allow_utf8_domains boolean false main 4.14
+arc_sign string* unset smtp 4.91 with Experimental_ARC
auth_advertise_hosts host list "*" main 4.00
authenticated_sender string* unset smtp 4.14
authenticated_sender_force boolean false smtp 4.61
command_group string unset queryprogram 4.00
command_timeout time 5m smtp
command_user string unset queryprogram 4.00
+commandline_checks_require_admin boolean false main 4.90
condition string* unset routers 4.00
connect_timeout time 0s smtp 1.60
connection_max_messages integer 500 smtp 4.00 replaces batch_max
daemon_smtp_ports string unset main 1.75 pluralised in 4.21
daemon_startup_retries int 9 main 4.52
daemon_startup_sleep time 30s main 4.52
+dane_require_tls_ciphers string* unset smtp 4.91
data string unset redirect 4.00
data_timeout time 5m smtp
debug_print string* unset authenticators 4.00
unset routers 4.00
unset transports 2.00
+debug_store boolean false main 4.90
delay_after_cutoff boolean true smtp
delay_warning time list 24h main
delay_warning_condition string* + main 1.73
dkim_selector string* unset smtp 4.70
dkim_sign_headers string* (RFC4871) smtp 4.70
dkim_strict string* unset smtp 4.70
+dkim_timestamps integer* unset smtp 4.92
dkim_verify_signers string* $dkim_signers main 4.70
directory string* unset appendfile
directory_file string* + appendfile
disable_ipv6 boolean false main 4.61
disable_logging boolean false routers 4.11
false transports 4.11
+dmarc_forensic_sender string unset main 4.82 if experimental_dmarc
+dmarc_history_file string unset main 4.82 if experimental_dmarc
+dmarc_tld_file string unset main 4.82 if experimental_dmarc
dns_again_means_nonexist domain list unset main 1.89
dns_check_names_pattern string + main 2.11
+dns_cname_loops integer 0 main 4.92 Set to 9 for older behaviour
dns_csa_search_limit integer 5 main 4.60
dns_csa_use_reverse boolean true main 4.60
+dns_dnssec_ok integer -1 main 4.82
+dns_dane_ok integer -1 main 4.83
dns_ipv4_lookup boolean false main 3.20
dns_qualify_single boolean true smtp
dns_retrans time 0s main 1.60
unset routers 4.00
unset transports
drop_cr boolean false main 4.00 became a no-op in 4.21
+dscp string unset smtp 4.82
dsn_from string* + main 4.67
envelope_to_add boolean false transports
envelope_to_remove boolean true main
forbid_pipe boolean false redirect 4.00
forbid_sieve_filter boolean false redirect 4.44
forbid_smtp_code boolean false redirect 4.63
+force_command boolean false pipe 4.82
freeze_exec_fail boolean false pipe 1.89
freeze_signal boolean false pipe 4.75
freeze_tell boolean false main 4.00 replaces freeze_tell_mailmaster
gecos_name string* unset main
gecos_pattern string unset main
gethostbyname boolean false smtp
+gnutls_allow_auto_pkcs11 boolean false main 4.82
gnutls_compat_mode boolean unset main 4.70
-gnutls_require_kx string* unset main 4.67
- string* unset smtp 4.67
-gnutls_require_mac string* unset main 4.67
- string* unset smtp 4.67
-gnutls_require_protocols string* unset main 4.67
- string* unset smtp 4.67
+gnutls_require_kx string* unset main 4.67 deprecated, warns
+ string* unset smtp 4.67 deprecated, warns
+gnutls_require_mac string* unset main 4.67 deprecated, warns
+ string* unset smtp 4.67 deprecated, warns
+gnutls_require_protocols string* unset main 4.67 deprecated, warns
+ string* unset smtp 4.67 deprecated, warns
group string + routers 4.00
unset transports 4.00 replaces local option in some transports
header_line_maxsize integer 0 (unset) main 4.14
hosts_max_try integer 5 smtp 3.20
hosts_max_try_hardlimit integer 50 smtp 4.50
hosts_nopass_tls host list unset smtp 4.00
+hosts_noproxy_tls host list "*" smtp 4.90
hosts_override boolean false smtp 2.11
+hosts_pipe_connect host_list unset smtp 4.93 if experimental_pipe_connect
hosts_randomize boolean false manualroute 4.00
false smtp 3.14
hosts_require_auth host list unset smtp 4.00
+hosts_require_dane host list unset smtp 4.91 (4.85 experimental)
+hosts_require_ocsp host list unset smtp 4.82 if experimental_ocsp
hosts_require_tls host list unset smtp 3.20
hosts_treat_as_local domain list unset main 1.95
hosts_try_auth host list unset smtp 4.00
+hosts_try_dane host list unset smtp 4.91 (4.85 experimental)
+hosts_try_fastopen host list unset smtp 4.88
+hosts_try_prdr host list unset smtp 4.82 if experimental_prdr
ibase_servers string unset main 4.23
ignore_bounce_errors_after time 0s main 4.00
ignore_eacces boolean false redirect 4.00
once_file_size integer 0 autoreply 3.20
once_repeat time 0s autoreply 2.95
one_time boolean false redirect 4.00
-openssl_options string unset main 4.73 default to unset in 4.78
+openssl_options string +no_sslv2 main 4.73 default changed in 4.80
optional boolean false iplookup 4.00
oracle_servers string unset main 4.00
owners string list unset redirect 4.00
pipe_as_creator boolean false pipe
pipe_transport string* unset redirect 4.00
pipelining_advertise_hosts host list "*" main 4.14
+pipelining__connect_advertise_hosts host list "*" main 4.92 if experimental_pipe_connect
port integer 0 iplookup 4.00
string "smtp" smtp
preserve_message_logs boolean false main
+prdr_enable boolean false main 4.82 if experimental_prdr
primary_hostname string + main
print_topbitchars boolean false main 1.89
process_log_path string unset main 4.21
senders address list unset routers 4.00
serialize_hosts host list unset smtp 1.60
server_advertise_condition string* unset authenticators 4.14
-server_channelbinding bool false gsasl 4.78
+server_channelbinding bool false gsasl 4.80
server_condition string* unset authenticators 3.10 (plaintext) 4.64 (others)
-server_hostname string* "$primary_hostname" cyrus_sasl,gsasl,heimdal_gssapi (cyrus-only) 4.78 (others)
-server_keytab string* unset heimdal_gssapi 4.78
+server_hostname string* "$primary_hostname" cyrus_sasl,gsasl,heimdal_gssapi (cyrus-only) 4.80 (others)
+server_keytab string* unset heimdal_gssapi 4.80
server_mail_auth_condition string* unset authenticators 3.22
-server_mech string public_name cyrus_sasl,gsasl 4.43 (cyrus-only) 4.78 (others)
-server_password string unset gsasl 4.78
+server_mech string public_name cyrus_sasl,gsasl 4.43 (cyrus-only) 4.80 (others)
+server_password string unset gsasl 4.80
+server_param1 string* unset tls (auth) 4.86
+server_param2 string* unset tls (auth) 4.86
+server_param3 string* unset tls (auth) 4.86
server_prompts string* unset plaintext 3.10
-server_realm string unset cyrus_sasl,gsasl 4.43 (cyrus-only) 4.78 (others)
-server_scram_iter string* unset gsasl 4.78
-server_scram_salt string* unset gsasl 4.78
+server_realm string unset cyrus_sasl,gsasl 4.43 (cyrus-only) 4.80 (others)
+server_scram_iter string* unset gsasl 4.80
+server_scram_salt string* unset gsasl 4.80
server_secret string* unset cram_md5 3.10
-server_service string "smtp" cyrus_sasl,gsasl,heimdal_gssapi (cyrus-only) 4.78 (others)
+server_service string "smtp" cyrus_sasl,gsasl,heimdal_gssapi (cyrus-only) 4.80 (others)
server_set_id string* unset authenticators 3.10
shadow_condition string* unset transports
shadow_transport string unset transports
spamd_address string* + main 4.50 with content scan
split_spool_directory boolean false main 1.70
spool_directory string ++ main
+spool_wireformat boolean false main 4.90
sqlite_lock_timeout time 5s main 4.53
strict_acl_vars boolean false main 4.64
srv_fail_domains domain list unset dnslookup 4.43
timeout_frozen_after time 0s main 3.20
timezone string + main 3.15
tls_advertise_hosts host list * main 3.20
+tls_advertise_requiretls host list * main 4.92 if experimental_requiretls
tls_certificate string* unset main 3.20
unset smtp 3.20
+tls_dh_max_bits integer 2236 main 4.80
+tls_dh_min_bits integer 1024 smtp 4.82
tls_dhparam string* unset main 3.20
+tls_ocsp_file string* unset main 4.80 if experimental_ocsp
tls_on_connect_ports string unset main 4.43
tls_privatekey string* unset main 3.20
unset smtp 3.20
tls_remember_emstp boolean false main 4.21
tls_require_ciphers string* unset smtp 4.00 replaces tls_verify_ciphers
string* unset main 4.33
-tls_sni string* unset main 4.78
+tls_sni string* unset main 4.80
tls_tempfail_tryclear boolean true smtp 4.05
tls_try_verify_hosts host list unset main 4.00
tls_verify_certificates string* unset main 3.20
use_shell boolean false pipe 1.70
user string + routers 4.00
unset transports 4.00 replaces individual options
+utf8_downconvert integer unset smtp 4.92 if SUPPORT_I18N
uucp_from_pattern string + main 1.75
uucp_from_sender string* "$1" main 1.75
verify boolean true routers 4.00
-bh Test incoming SMTP call, omitting callouts
-bhc Test incoming SMTP call, with callouts
-bi * Run <command>bi_command</command>
+-bI:help Show list of accepted -bI:<tag> options
-bm Accept message on standard input
-bmalware + Invoke configured malware scanning against supplied filename
-bnq Don't qualify addresses in locally submitted messages
-oMai # Supply authenticated id
-oMas # Supply authenticated sender
-oMi # Supply interface address
+-oMm # Supply message reference
-oMr # Supply protocol name
-oMs # Supply host name
-oMt # Supply ident string
DELIVER_IN_BUFFER_SIZE optional*
DELIVER_OUT_BUFFER_SIZE optional*
DISABLE_DKIM optional disables DKIM support
+DISABLE_DNSSEC optional disables attempts to use DNSSEC
DISABLE_D_OPTION optional disables -D option
ERRNO_QUOTA optional* error code for system quota failures
EXICYCLOG_MAX optional number of old log files to keep
EXIM_PERL optional
EXIM_USER mandatory user to use for Exim
EXIWHAT_EGREP_ARG system** to find Exim processes from ps
-EXIWHAT_KILL_SIGNAL system** -SIGUSER1 or numerical equivalent
+EXIWHAT_KILL_SIGNAL system** -SIGUSR1 or numerical equivalent
EXIWHAT_MULTIKILL_CMD system**
EXIWHAT_MULTIKILL_ARG system**
EXIWHAT_PS_ARG system** to list all processes
TIMEZONE_DEFAULT optional default for timezone option
TLS_INCLUDE optional path to include files for TLS
TLS_LIBS optional additional libraries for TLS
-TMPDIR system value for TMPDIR environment variable
+EXIM_TMPDIR system value for TMPDIR environment variable
TRANSPORT_APPENDFILE driver include appendfile transport
TRANSPORT_AUTOREPLY driver include autoreply transport
TRANSPORT_LMTP driver include lmtp transport