Before an upgrade:
1) Remember to make backup/export files before an upgrade and save them on another storage device;
2) Make sure the device will not lose power during upgrade process;
3) Device has enough free storage space for all RouterOS packages to be downloaded.
What's new in 6.42 (2018-Apr-13 11:03):
!) tile - improved system performance and stability ("/system routerboard upgrade" required);
!) w60g - increased distance for wAP 60G to 200+ meters;
bridge - added host aging timer for CRS3xx and Atheros hw-bridges; bridge - added per-port forwarding options for broadcasts, unknown-multicasts and unknown-unicasts; bridge - added per-port learning options; bridge - added support for static hosts; bridge - fixed "master-port" configuration conversion from pre-v6.41 RouterOS versions; bridge - fixed bridge port interface parameter under "/interface bridge host print detail"; bridge - fixed false MAC address learning on hAP ac^2 and cAP ac devices; bridge - fixed incorrect "fast-forward" enabling when ports were switched; bridge - fixed MAC learning for VRRP interfaces on bridge; bridge - fixed reliability on software bridges when used on devices without switch chip; bridge - hide options for disabled bridge features in CLI; bridge - show "hw" flags only on Ethernet interfaces and interface lists; capsman - added "allow-signal-out-of-range" option for Access List entries; capsman - added support for "interface-list" in Access List and Datapath entries; capsman - improved CAPsMAN responsiveness with large amount of CAP interfaces; capsman - log "signal-strength" when successfully connected to AP; certificate - added PKCS#10 version check; certificate - dropped DES support and added AES instead for SCEP; certificate - dropped MD5 support and require SHA1 as minimum for SCEP; certificate - fixed incorrect SCEP URL after an upgrade; chr - added "open-vm-tools" on VMware installations; chr - added "qemu-guest-agent" and "virtio-scsi" driver on KVM installations; chr - added "xe-daemon" on Xen installations; chr - added support for Amazon Elastic Network Adapter (ENA) driver; chr - added support for booting from NVMe disks; chr - added support for Hyper-V ballooning, guest quiescing, host-guest file transfer, integration services and static IP injection; chr - added support for NIC hot-plug on VMware and Xen installations; chr - fixed additional disk detaching on Xen installations; chr - fixed interface matching by name on VMware installations; chr - fixed interface naming order when adding more than 4 interfaces on VMware installations; chr - fixed suspend on Xen installations; chr - make additional disks visible under "/disk" on Xen installations; chr - make Virtio disks visible under "/disk" on KVM installations; chr - run startup scripts on the first boot on AWS and Google Cloud installations; console - fixed "idpr-cmtp" protocol by changing its value from 39 to 38; console - improved console stability after it has not been used for a long time; crs1xx/2xx - added BPDU value for "ingress-vlan-translation" menu "protocol" option; crs212 - fixed Ethernet boot when connected to boot server through CRS326 device; crs326 - fixed known multicast flooding to the CPU; crs3xx - added switch port "storm-rate" limiting options; crs3xx - added “hw-offload” support for 802.3ad and “balance-xor” bonding; detnet - fixed "detect-internet" feature unavailability if router had too long identity (introduced in v6.41); dhcp - improved DHCP service reliability when it is configured on bridge interface; dhcp - reduced resource usage of DHCP services; dhcpv4-server - added "dns-none" option to "/ip dhcp-server network dns"; dhcpv6 - make sure that time is set before restoring bindings; dhcpv6-client - added info exchange support; dhcpv6-client - added possibility to specify options; dhcpv6-client - added support for options 15 and 16; dhcpv6-client - implement confirm after reboot; dhcpv6-server - added DHCPv4 style user options; dns - do not generate "Undo" messages on changes to dynamic servers; email - set maximum number of sessions to 100; fetch - added "http-content-type" option to allow setting MIME type of the data in free text form; fetch - added "output" option for all modes in order to return result to file, variable or ignore it; fetch - increased maximum number of sessions to 100; filesystem - implemented additional system storage maintenance checks on ARM CPU based devices; flashfig - properly apply configuration provided by Flashfig; gps - improved NMEA sentence handling; health - added log warning when switching between redundant power supplies; health - fixed empty measurements on CRS328-24P-4S+RM; hotspot - improved HTTPS matching in Walled Garden rules; ike1 - display error message when peer requests "mode-config" when it is not configured; ike1 - do not accept "mode-config" reply more than once; ike1 - fixed wildcard policy lookup on responder; ike2 - fixed framed IP address received from RADIUS server; interface - improved interface configuration responsiveness; ippool - added ability to specify comment; ippool6 - added pool name to "no more addresses left" error message; ipsec - fixed AES-CTR and AES-GCM support on RB1200; ipsec - improved single tunnel hardware acceleration performance on MMIPS devices; ipsec - properly detect interface for "mode-config" client IP address assignment; ipv6 - fixed IPv6 behaviour when bridge port leaves bridge; ipv6 - update IPv6 DNS from RA only when it is changed; kidcontrol - initial work on "/ip kid-control" feature; led - added "Dark Mode" support for wAP 60G; led - added w60g alignment trigger; led - fixed unused "link-act-led" LED trigger on RBLHG 2nD, RBLHG 2nD-XL and RBSXTsq 2nD; led - removed unused "link-act-led" trigger for devices which does not use it; lte - added initial support for Quectel LTE EP06-E; lte - added initial support for SIM7600 LTE modem interface; lte - added support for the user and password authentication for wAP-LTE-kit-US (R11e-LTE-US); lte - do not add DHCP client on LTE modems that doesn't use DHCP; lte - fixed DHCP client adding for MF823 modem; lte - fixed LTE band setting for SXT LTE; mac-ping - fixed duplicate responses; modem - added initial support for AC340U; netinstall - fixed MMIPS RouterOS package description; netinstall - sign Netinstall executable with an Extended Validation Code Signing Certificate; netwatch - limit to read, write, test and reboot policies for Netwatch script execution; poe - do not show "poe-out-current" on devices which can not determine it; poe - hide PoE related properties on interfaces that does not provide power output; ppp - added initial support for NETGEAR AC340U and ZyXEL WAH1604; ppp - allow to override remote user PPP profile via "Mikrotik-Group"; quickset - fixed NAT if PPPoE client is used for Internet access; quickset - properly detect IP address when one of the bridge modes is used; quickset - properly detect LTE interface on startup; quickset - show "G" flag for guest users; quickset - use "/24" subnet for local network by default; r11e-lte - improved LTE connection initialization process; rb1100ahx4 - improved reliability on hardware encryption; routerboard - added RouterBOOT "auto-upgrade" after RouterOS upgrade (extra reboot required); routerboard - properly detect hAP ac^2 RAM size; sniffer - fixed "/tool sniffer packet" results listed in incorrect order; snmp - added "/caps-man interface print oid"; snmp - added "/interface w60g print oid"; snmp - added "board-name" OID; snmp - improved request processing performance for wireless and CAP interfaces; ssh - fixed SSH service becoming unavailable; ssh - generate SSH keys only on the first connect attempt instead of the first boot; ssh - improved key import error messages; ssh - remove imported public SSH keys when their owner user is removed; switch - hide "ingress-rate" and "egress-rate" for non-CRS3xx switches; tile - added "aes-ctr" hardware acceleration support; tr069-client - added "DownloadDiagnostics" and "UploadDiagnostics"; tr069-client - correctly return “TransferComplete” after vendor configuration file transfer; tr069-client - fixed "/tool fetch" commands executed with ".alter" script; tr069-client - fixed HTTPS authentication process; traffic-flow - fixed IPv6 destination address value when IPFIX protocol is used; upgrade - improved RouterOS upgrade process and restrict upgrade from RouterOS older than v5.16; ups - improved communication between router and UPS; ups - improved disconnect message handling between RouterOS and UPS; userman - added support for ARM and MMIPS platform; w60g - added "tx-power" setting (CLI only); w60g - added RSSI information (CLI only); w60g - added TX sector alignment information (CLI only); watchdog - retry to send "autosupout.rif" file to an e-mail if initial delivery failed up to 3 times within 20 second interval; winbox - added "antenna" setting under GPS settings for MIPS platform devices; winbox - added "crl-store" setting to certificate settings; winbox - added "insert-queue-before" to DHCP server; winbox - added "use-dn" setting in OSPF instance General menu; winbox - added 160 MHz "channel-width" to wireless settings; winbox - added DHCPv6 client info request type and updated statuses; winbox - added missing protocol numbers to IPv4 and IPv6 firewall; winbox - added possibility to delete SMS from inbox; winbox - allow to comment new object without committing it; winbox - allow to open bridge host entry; winbox - fixed name for "out-bridge-list" parameter under bridge firewall rules; winbox - fixed typo from "UPtime" to "Uptime"; winbox - fixed Winbox closing when viewing graph which does not contain any data; winbox - improved stability when using trackpad scrolling in large lists; winbox - made UDP local and remote TX size parameters optional in Bandwidth Test tool; winbox - moved "ageing-time" setting from STP to General tab; winbox - moved OSPF instance "routing-table" setting in OSPF instance General menu; winbox - removed “VLAN” section from “Switch” menu for CRS3xx devices; winbox - show Bridge Port PVID column by default; winbox - show CQI in LTE info; winbox - show dual SIM options only for RouterBOARDS which does have two SIM slots; winbox - show only master CAP interfaces under CAPsMAN wireless scan tool; winbox - use proper graph name for HDD graphs; wireless - added "realm-raw" setting for "/interface wireless interworking-profiles" (CLI only); wireless - added initial support for "nstreme-plus"; wireless - added support for "band=5ghz-n/ac"; wireless - added support for "interface-list" for Access List entries; wireless - added support for legacy AR9485 chipset; wireless - enable all chains by default on devices without external antennas after configuration reset; wireless - fixed "wds-slave" channel selection when single frequency is specified; wireless - fixed incompatibility with macOS clients; wireless - fixed long "scan-list" entries not working for ARM based wireless interfaces; wireless - fixed nv2 protocol on ARM platform SXTsq devices; wireless - fixed RB911-5HnD low transmit power issue; wireless - fixed RTS/CTS option for the ARM based wireless devices; wireless - fixed wsAP wrong 5 GHz interface MAC address; wireless - improved compatibility with specific wireless AC standard clients; wireless - improved Nv2 PtMP performance; wireless - improved packet processing on ARM platform devices; wireless - improved wireless performance on hAP ac^2 devices while USB is being used; wireless - improved wireless scan functionality;
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