Add ntsaeads directive to enable only selected AEAD algorithms for NTS

Negotiate use of compliant NTS keys with AES-128-GCM-SIV AEAD algorithm (by default the keys are generated differently than in RFC 8915 for compatibility with chrony server and client versions 4.4, 4.5, and 4.6)

Switch to compliant NTS keys if first response from server is NTS NAK

Add activate option to local directive to set activation threshold

Add ipv4 and ipv6 options to server/pool/peer directive

Add kod option to ratelimit directive for server KoD RATE support

Add leapseclist directive to read NIST/IERS leap-seconds.list file

Add ptpdomain directive to set PTP domain for NTP over PTP

Allow disabling pidfile

Improve copy server option to accept unsynchronised status instantly

Log one selection failure on start

Add offset command to modify source offset correction

Add timestamp sources to ntpdata report

Fix crash on sources reload during initstepslew or RTC initialisation

Fix source refreshment to not repeat failed name resolving attempts

Add support for AES-GCM-SIV in GnuTLS

Add support for corrections from PTP transparent clocks

Add support for systemd socket activation

Fix presend in interleaved mode

Fix reloading of modified sources from sourcedir

Add support for AES-GCM-SIV with Nettle >= 3.9 to shorten NTS cookies to avoid some length-specific blocking of NTP on Internet

Add support for multiple refclocks using extpps option on one PHC

Add maxpoll option to hwtimestamp directive to improve PHC tracking with low packet rates

Add hwtstimeout directive to configure timeout for late timestamps

Handle late hardware transmit timestamps of NTP requests on all sockets

Handle mismatched 32/64-bit time_t in SOCK refclock samples

Improve source replacement

Log important changes made by command requests (chronyc)

Refresh address of NTP sources periodically

Request nanosecond kernel RX timestamping on FreeBSD

Set DSCP for IPv6 packets

Shorten NTS-KE retry interval when network is down

Update seccomp filter for musl

Warn if loading keys from file with unexpected permissions

Warn if source selection fails or falseticker is detected

Add selectopts command to modify source-specific selection options

Add timestamp sources to serverstats report and make its fields 64-bit

Add -e option to chronyc to indicate end of response

Add local option to refclock directive to stabilise system clock with more stable free-running clock (e.g. TCXO, OCXO)

Add maxdelayquant option to server/pool/peer directive to replace maxdelaydevratio filter with long-term quantile-based filtering

Add selection option to log directive

Allow external PPS in PHC refclock without configurable pin

Don’t accept first interleaved response to minimise error in delay

Don’t use arc4random on Linux to avoid server performance loss

Improve filter option to better handle missing NTP samples

Improve stability with hardware timestamping and PHC refclock

Update seccomp filter

Fix waitsync command to reconnect when not getting response

Add support for NTPv4 extension field improving synchronisation stability and resolution of root delay and dispersion (experimental)

Add support for NTP over PTP (experimental)

Add support for AES-CMAC and hash functions in GnuTLS

Improve server interleaved mode to be more reliable and support multiple clients behind NAT

Update seccomp filter

Add statistics about interleaved mode to serverstats report

Fix RTC support with 64-bit time_t on 32-bit Linux

Fix seccomp filter to work correctly with bind*device directives

Suppress kernel adjustments of system clock (dosynctodr) on illumos

Switch Solaris support to illumos

Add support for NTS servers specified by IP address (matching Subject Alternative Name in server certificate)

Add source-specific configuration of trusted certificates

Allow multiple files and directories with trusted certificates

Allow multiple pairs of server keys and certificates

Add copy option to server/pool directive

Increase PPS lock limit to 40% of pulse interval

Perform source selection immediately after loading dump files

Reload dump files for addresses negotiated by NTS-KE server

Update seccomp filter and add less restrictive level

Restart ongoing name resolution on online command

Fix responding to IPv4 command requests on FreeBSD

Fix dump files to not include uncorrected offset

Fix initstepslew to accept time from own NTP clients

Reset NTP address and port when no longer negotiated by NTS-KE server

Add support for Network Time Security (NTS) authentication

Add support for AES-CMAC keys (AES128, AES256) with Nettle

Add authselectmode directive to control selection of unauthenticated sources

Add binddevice, bindacqdevice, bindcmddevice directives

Add confdir directive to better support fragmented configuration

Add sourcedir directive and "reload sources" command to support dynamic NTP sources specified in files

Add clockprecision directive

Add dscp directive to set Differentiated Services Code Point (DSCP)

Add -L option to limit log messages by severity

Add -p option to print whole configuration with included files

Add -U option to allow start under non-root user

Allow maxsamples to be set to 1 for faster update with -q/-Q option

Avoid replacing NTP sources with sources that have unreachable address

Improve pools to repeat name resolution to get "maxsources" sources

Improve source selection with trusted sources

Improve NTP loop test to prevent synchronisation to itself

Repeat iburst when NTP source is switched from offline state to online

Update clock synchronisation status and leap status more frequently

Update seccomp filter

Add "add pool" command

Add "reset sources" command to drop all measurements

Add authdata command to print details about NTP authentication

Add selectdata command to print details about source selection

Add -N option and sourcename command to print original names of sources

Add -a option to some commands to print also unresolved sources

Add -k, -p, -r options to clients command to select, limit, reset data

Don’t set interface for NTP responses to allow asymmetric routing

Handle RTCs that don’t support interrupts

Respond to command requests with correct address on multihomed hosts

Drop support for RIPEMD keys (RMD128, RMD160, RMD256, RMD320)

Drop support for long (non-standard) MACs in NTPv4 packets (chrony 2.x clients using non-MD5/SHA1 keys need to use option "version 3")

Drop support for line editing with GNU Readline

Create new file when writing pidfile (CVE-2020-14367)

Add support for more accurate reading of PHC on Linux 5.0

Add support for hardware timestamping on interfaces with read-only timestamping configuration

Add support for memory locking and real-time priority on FreeBSD, NetBSD, Solaris

Update seccomp filter to work on more architectures

Validate refclock driver options

Fix bindaddress directive on FreeBSD

Fix transposition of hardware RX timestamp on Linux 4.13 and later

Fix building on non-glibc systems

Add filter option to server/pool/peer directive

Add minsamples and maxsamples options to hwtimestamp directive

Add support for faster frequency adjustments in Linux 4.19

Change default pidfile to /var/run/chrony/chronyd.pid to allow chronyd without root privileges to remove it on exit

Disable sub-second polling intervals for distant NTP sources

Extend range of supported sub-second polling intervals

Get/set IPv4 destination/source address of NTP packets on FreeBSD

Make burst options and command useful with short polling intervals

Modify auto_offline option to activate when sending request failed

Respond from interface that received NTP request if possible

Add onoffline command to switch between online and offline state according to current system network configuration

Improve example NetworkManager dispatcher script

Avoid waiting in Linux getrandom system call

Fix PPS support on FreeBSD and NetBSD

Add burst option to server/pool directive

Add stratum and tai options to refclock directive

Add support for Nettle crypto library

Add workaround for missing kernel receive timestamps on Linux

Wait for late hardware transmit timestamps

Improve source selection with unreachable sources

Improve protection against replay attacks on symmetric mode

Allow PHC refclock to use socket in /var/run/chrony

Add shutdown command to stop chronyd

Simplify format of response to manual list command

Improve handling of unknown responses in chronyc

Respond to NTPv1 client requests with zero mode

Fix -x option to not require CAP_SYS_TIME under non-root user

Fix acquisitionport directive to work with privilege separation

Fix handling of socket errors on Linux to avoid high CPU usage

Fix chronyc to not get stuck in infinite loop after clock step

Improve stability with NTP sources and reference clocks

Improve stability with hardware timestamping

Improve support for NTP interleaved modes

Control frequency of system clock on macOS 10.13 and later

Set TAI-UTC offset of system clock with leapsectz directive

Minimise data in client requests to improve privacy

Allow transmit-only hardware timestamping

Add support for new timestamping options introduced in Linux 4.13

Add root delay, root dispersion and maximum error to tracking log

Add mindelay and asymmetry options to server/peer/pool directive

Add extpps option to PHC refclock to timestamp external PPS signal

Add pps option to refclock directive to treat any refclock as PPS

Add width option to refclock directive to filter wrong pulse edges

Add rxfilter option to hwtimestamp directive

Add -x option to disable control of system clock

Add -l option to log to specified file instead of syslog

Allow multiple command-line options to be specified together

Allow starting without root privileges with -Q option

Update seccomp filter for new glibc versions

Dump history on exit by default with dumpdir directive

Use hardening compiler options by default

Don’t drop PHC samples with low-resolution system clock

Ignore outliers in PHC tracking, RTC tracking, manual input

Increase polling interval when peer is not responding

Exit with error message when include directive fails

Don’t allow slash after hostname in allow/deny directive/command

Try to connect to all addresses in chronyc before giving up

Add support for precise cross timestamping of PHC on Linux

Add minpoll, precision, nocrossts options to hwtimestamp directive

Add rawmeasurements option to log directive and modify measurements option to log only valid measurements from synchronised sources

Allow sub-second polling interval with NTP sources

Fix time smoothing in interleaved mode

Add support for software and hardware timestamping on Linux

Add support for client/server and symmetric interleaved modes

Add support for MS-SNTP authentication in Samba

Add support for truncated MACs in NTPv4 packets

Estimate and correct for asymmetric network jitter

Increase default minsamples and polltarget to improve stability with very low jitter

Add maxjitter directive to limit source selection by jitter

Add offset option to server/pool/peer directive

Add maxlockage option to refclock directive

Add -t option to chronyd to exit after specified time

Add partial protection against replay attacks on symmetric mode

Don’t reset polling interval when switching sources to online state

Allow rate limiting with very short intervals

Improve maximum server throughput on Linux and NetBSD

Remove dump files after start

Add tab-completion to chronyc with libedit/readline

Add ntpdata command to print details about NTP measurements

Allow all source options to be set in add server/peer command

Indicate truncated addresses/hostnames in chronyc output

Print reference IDs as hexadecimal numbers to avoid confusion with IPv4 addresses

Fix crash with disabled asynchronous name resolving

Fix processing of kernel timestamps on non-Linux systems

Fix crash with smoothtime directive

Fix validation of refclock sample times

Fix parsing of refclock directive

Add orphan option to local directive for orphan mode compatible with ntpd

Add distance option to local directive to set activation threshold (1 second by default)

Add maxdrift directive to set maximum allowed drift of system clock

Try to replace NTP sources exceeding maximum distance

Randomise source replacement to avoid getting stuck with bad sources

Randomise selection of sources from pools on start

Ignore reference timestamp as ntpd doesn’t always set it correctly

Modify tracking report to use same values as seen by NTP clients

Add -c option to chronyc to write reports in CSV format

Provide detailed manual pages

Fix SOCK refclock to work correctly when not specified as last refclock

Fix initstepslew and -q/-Q options to accept time from own NTP clients

Fix authentication with keys using 512-bit hash functions

Fix crash on exit when multiple signals are received

Fix conversion of very small floating-point numbers in command packets

Drop documentation in Texinfo format

Add support for NTP and command response rate limiting

Add support for dropping root privileges on Mac OS X, FreeBSD, Solaris

Add require and trust options for source selection

Enable logchange by default (1 second threshold)

Set RTC on Mac OS X with rtcsync directive

Allow binding to NTP port after dropping root privileges on NetBSD

Drop CAP_NET_BIND_SERVICE capability on Linux when NTP port is disabled

Resolve names in separate process when seccomp filter is enabled

Replace old records in client log when memory limit is reached

Don’t reveal local time and synchronisation state in client packets

Don’t keep client sockets open for longer than necessary

Ignore poll in KoD RATE packets as ntpd doesn’t always set it correctly

Warn when using keys shorter than 80 bits

Add keygen command to generate random keys easily

Add serverstats command to report NTP and command packet statistics

Fix clock correction after making step on Mac OS X

Fix building on Solaris

Restrict authentication of NTP server/peer to specified key (CVE-2016-1567)

Add support for configuration and monitoring over Unix domain socket (accessible by root or chrony user when root privileges are dropped)

Add support for system call filtering with seccomp on Linux (experimental)

Add support for dropping root privileges on NetBSD

Control frequency of system clock on FreeBSD, NetBSD, Solaris

Add system leap second handling mode on FreeBSD, NetBSD, Solaris

Add dynamic drift removal on Mac OS X

Add support for setting real-time priority on Mac OS X

Add maxdistance directive to limit source selection by root distance (3 seconds by default)

Add refresh command to get new addresses of NTP sources

Allow wildcard patterns in include directive

Restore time from driftfile with -s option if later than RTC time

Add configure option to set default hwclockfile

Add -d option to chronyc to enable debug messages

Allow multiple addresses to be specified for chronyc with -h option and reconnect when no valid reply is received

Make check interval in waitsync command configurable

Fix building on NetBSD, Solaris

Restore time from driftfile with -s option if reading RTC failed

Drop support for authentication with command key (run-time configuration is now allowed only for local users that can access the Unix domain socket)

Fix clock stepping by integer number of seconds on Linux

Add support for Mac OS X

Try to replace unreachable and falseticker servers/peers specified by name like pool sources

Add leaponly option to smoothtime directive to allow synchronised leap smear between multiple servers

Use specific reference ID when smoothing served time

Add smoothing command to report time smoothing status

Add smoothtime command to activate or reset time smoothing

Fix crash in source selection with preferred sources

Fix resetting of time smoothing

Include packet precision in peer dispersion

Fix crash in chronyc on invalid command syntax

Update to NTP version 4 (RFC 5905)

Add pool directive to specify pool of NTP servers

Add leapsecmode directive to select how to correct clock for leap second

Add smoothtime directive to smooth served time and enable leap smear

Add minsources directive to set required number of selectable sources

Add minsamples and maxsamples options for all sources

Add tempcomp configuration with list of points

Allow unlimited number of NTP sources, refclocks and keys

Allow unreachable sources to remain selected

Improve source selection

Handle offline sources as unreachable

Open NTP server port only when necessary (client access is allowed by allow directive/command or peer/broadcast is configured)

Change default bindcmdaddress to loopback address

Change default maxdelay to 3 seconds

Change default stratumweight to 0.001

Update adjtimex synchronisation status

Use system headers for adjtimex

Check for memory allocation errors

Reduce memory usage

Add configure options to compile without NTP, cmdmon, refclock support

Extend makestep command to set automatic clock stepping

Add sanity checks for time and frequency offset

Don’t report synchronised status during leap second

Don’t combine reference clocks with close NTP sources

Fix accepting requests from configured sources

Fix initial fallback drift setting

Protect authenticated symmetric NTP associations against DoS attacks (CVE-2015-1853)

Fix access configuration with subnet size indivisible by 4 (CVE-2015-1821)

Fix initialization of reply slots for authenticated commands (CVE-2015-1822)

Support operation in other NTP eras (next era begins in 2036), NTP time is mapped to [-50, +86] years around build date by default

Restore time from driftfile with -s when RTC is missing/unsupported

Close connected client sockets when not waiting for reply

Use one client socket with random port when acquisitionport is 0

Use NTP packets instead of UDP echo for presend

Don’t adjust polling interval when sending fails

Allow binding to addresses that don’t exist yet

Ignore measurements around leap second

Improve detection of unexpected time jumps

Include example of logrotate configuration, systemd services and NetworkManager dispatcher script

Reconnect client sockets for each request to follow changes in network configuration automatically

Restart timer when polling interval is changed on reset

Add asynchronous name resolving with POSIX threads

Add PTP hardware clock (PHC) refclock driver

Add new generic clock driver to slew by adjusting frequency only (without kernel PLL or adjtime) and use it on Linux

Add rtcautotrim directive to trim RTC automatically

Add hwclockfile directive to share RTC LOCAL/UTC setting with hwclock

Add maxslewrate directive to set maximum allowed slew rate

Add maxdispersion option for refclocks

Add -q/-Q options to set clock/print offset once and exit

Allow directives to be specified on chronyd command line

Replace frequency scaling in Linux driver with retaining of tick

Try to detect unexpected forward time jumps and reset state

Exit with non-zero code when maxchange limit is reached

Improve makestep to not start and stop slew unnecessarily

Change default corrtimeratio to 3.0 to improve frequency accuracy

Announce leap second only on last day of June and December

Use separate connected client sockets for each NTP server

Remove separate NTP implementation used for initstepslew

Limit maximum minpoll set by KoD RATE to default maxpoll

Don’t send NTP requests with unknown key

Print warning when source is added with unknown key

Take leap second in PPS refclock from locked source

Make reading of RTC for initial trim more reliable

Don’t create cmdmon sockets when cmdport is 0

Add configure option to set default user to drop root privileges

Add configure option to compile with debug messages

Print debug messages when -d is used more than once

Change format of messages written to terminal with -d

Write fatal messages also to stderr with -n

Use IP_RECVERR socket option in chronyc to not wait unnecessarily

Shorten default chronyc timeout for localhost

Change default hostname in chronyc from localhost to 127.0.0.1

Print error message on invalid syntax with all chronyc commands

Include simulation test suite using clknetsim

Fix crash when selecting with multiple preferred sources

Fix frequency calculation with large frequency offsets

Fix code writing drift and RTC files to compile correctly

Fix -4/-6 options in chronyc to not reset hostname set by -h

Fix refclock sample validation with sub-second polling interval

Set stratum correctly with non-PPS SOCK refclock and local stratum

Modify dispersion accounting in refclocks to prevent PPS getting stuck with large dispersion and not accepting new samples