How does the timezone/timestamps of sale notifications work?

The table below shows exactly what time stamps will merchant and affiliate receive after a sale is done in other timezone. Timezone set for merchant or affiliate depending on the last known login to their merchant/affiliate panel and the location from which it was made.

Customer makes a sale from Japan.  server with installed Post Affiliate Pro has by default timezone set to America/Los_Angeles. Merchant's last known login was made from New York and affiliate's from Berlin. In their panels they would see the time of the click/commission with different timestamps calculated based on their timezone.
 
Merchant Server Affiliate Customer
USA - New York America - Los Angeles Europe - Berlin Japan - Tokio
GMT -05:00 GMT -08:00 GMT +01:00 GMT +09:00
Merchant receives notification that the sale was made at 05:04 AM local time. Transaction is saved into server database with time stamp 2:04 AM local time. Affiliate receives notification that sale was made at 11:04 AM local time. Customer makes a purchase at 06:04 PM local time.
Server time is used for sending daily, weekly, monthly email reports, when you are importing data via CSV, it can be selected when doing CSV exports, it is used for grouping of clicks commissions.

Change server time of your installation

You can set server timezone in merchant panel > Configuration >  Languages and Regional settings > Time Zone settings tab 

For older versions than 5.5.48.2, you need to add a setting into your Post Affiliate Pro database. Open the database and add a new record to qu_g_settings table (if there exists row with name: 'TIMEZONE' edit it):

- settingid is integer value filled automatically so you can let it empty (versions older than 5.3.27.6 set to a unique 8 characters string)
- name has to be set to TIMEZONE
- value will be your desired time zone (see the tables below).
- accountid can stay empty
 

example of sql insert command:
INSERT INTO `qu_g_settings` (`name`, `value`) VALUES ('TIMEZONE', 'America/Los_Angeles');

Note: In versions older than 5.0.9.5 this setting used to be in accounts > settings.php file, where you would add a line like TIMEZONE=America/Los_Ageneles


Here is a list of time zones:
Africa
Africa/Abidjan Africa/Accra Africa/Addis_Ababa Africa/Algiers Africa/Asmara
Africa/Asmera Africa/Bamako Africa/Bangui Africa/Banjul Africa/Bissau
Africa/Blantyre Africa/Brazzaville Africa/Bujumbura Africa/Cairo Africa/Casablanca
Africa/Ceuta Africa/Conakry Africa/Dakar Africa/Dar_es_Salaam Africa/Djibouti
Africa/Douala Africa/El_Aaiun Africa/Freetown Africa/Gaborone Africa/Harare
Africa/Johannesburg Africa/Kampala Africa/Khartoum Africa/Kigali Africa/Kinshasa
Africa/Lagos Africa/Libreville Africa/Lome Africa/Luanda Africa/Lubumbashi
Africa/Lusaka Africa/Malabo Africa/Maputo Africa/Maseru Africa/Mbabane
Africa/Mogadishu Africa/Monrovia Africa/Nairobi Africa/Ndjamena Africa/Niamey
Africa/Nouakchott Africa/Ouagadougou Africa/Porto-Novo Africa/Sao_Tome Africa/Timbuktu
Africa/Tripoli Africa/Tunis Africa/Windhoek  
 
America
America/Adak America/Anchorage America/Anguilla America/Antigua America/Araguaina
America/Argentina/Buenos_Aires America/Argentina/Catamarca America/Argentina/ComodRivadavia America/Argentina/Cordoba America/Argentina/Jujuy
America/Argentina/La_Rioja America/Argentina/Mendoza America/Argentina/Rio_Gallegos America/Argentina/San_Juan America/Argentina/San_Luis
America/Argentina/Tucuman America/Argentina/Ushuaia America/Aruba America/Asuncion America/Atikokan
America/Atka America/Bahia America/Barbados America/Belem America/Belize
America/Blanc-Sablon America/Boa_Vista America/Bogota America/Boise America/Buenos_Aires
America/Cambridge_Bay America/Campo_Grande America/Cancun America/Caracas America/Catamarca
America/Cayenne America/Cayman America/Chicago America/Chihuahua America/Coral_Harbour
America/Cordoba America/Costa_Rica America/Cuiaba America/Curacao America/Danmarkshavn
America/Dawson America/Dawson_Creek America/Denver America/Detroit America/Dominica
America/Edmonton America/Eirunepe America/El_Salvador America/Ensenada America/Fort_Wayne
America/Fortaleza America/Glace_Bay America/Godthab America/Goose_Bay America/Grand_Turk
America/Grenada America/Guadeloupe America/Guatemala America/Guayaquil America/Guyana
America/Halifax America/Havana America/Hermosillo America/Indiana/Indianapolis America/Indiana/Knox
America/Indiana/Marengo America/Indiana/Petersburg America/Indiana/Tell_City America/Indiana/Vevay America/Indiana/Vincennes
America/Indiana/Winamac America/Indianapolis America/Inuvik America/Iqaluit America/Jamaica
America/Jujuy America/Juneau America/Kentucky/Louisville America/Kentucky/Monticello America/Knox_IN
America/La_Paz America/Lima America/Los_Angeles America/Louisville America/Maceio
America/Managua America/Manaus America/Marigot America/Martinique America/Mazatlan
America/Mendoza America/Menominee America/Merida America/Mexico_City America/Miquelon
America/Moncton America/Monterrey America/Montevideo America/Montreal America/Montserrat
America/Nassau America/New_York America/Nipigon America/Nome America/Noronha
America/North_Dakota/Center America/North_Dakota/New_Salem America/Panama America/Pangnirtung America/Paramaribo
America/Phoenix America/Port-au-Prince America/Port_of_Spain America/Porto_Acre America/Porto_Velho
America/Puerto_Rico America/Rainy_River America/Rankin_Inlet America/Recife America/Regina
America/Resolute America/Rio_Branco America/Rosario America/Santiago America/Santo_Domingo
America/Sao_Paulo America/Scoresbysund America/Shiprock America/St_Barthelemy America/St_Johns
America/St_Kitts America/St_Lucia America/St_Thomas America/St_Vincent America/Swift_Current
America/Tegucigalpa America/Thule America/Thunder_Bay America/Tijuana America/Toronto
America/Tortola America/Vancouver America/Virgin America/Whitehorse America/Winnipeg
America/Yakutat America/Yellowknife      
 
Antarctica
Antarctica/Casey Antarctica/Davis Antarctica/DumontDUrville Antarctica/Mawson Antarctica/McMurdo
Antarctica/Palmer Antarctica/Rothera Antarctica/South_Pole Antarctica/Syowa Antarctica/Vostok
 
Arctic
Arctic/Longyearbyen
 
Asia
Asia/Aden Asia/Almaty Asia/Amman Asia/Anadyr Asia/Aqtau
Asia/Aqtobe Asia/Ashgabat Asia/Ashkhabad Asia/Baghdad Asia/Bahrain
Asia/Baku Asia/Bangkok Asia/Beirut Asia/Bishkek Asia/Brunei
Asia/Calcutta Asia/Choibalsan Asia/Chongqing Asia/Chungking Asia/Colombo
Asia/Dacca Asia/Damascus Asia/Dhaka Asia/Dili Asia/Dubai
Asia/Dushanbe Asia/Gaza Asia/Harbin Asia/Ho_Chi_Minh Asia/Hong_Kong
Asia/Hovd Asia/Irkutsk Asia/Istanbul Asia/Jakarta Asia/Jayapura
Asia/Jerusalem Asia/Kabul Asia/Kamchatka Asia/Karachi Asia/Kashgar
Asia/Katmandu Asia/Kolkata Asia/Krasnoyarsk Asia/Kuala_Lumpur Asia/Kuching
Asia/Kuwait Asia/Macao Asia/Macau Asia/Magadan Asia/Makassar
Asia/Manila Asia/Muscat Asia/Nicosia Asia/Novosibirsk Asia/Omsk
Asia/Oral Asia/Phnom_Penh Asia/Pontianak Asia/Pyongyang Asia/Qatar
Asia/Qyzylorda Asia/Rangoon Asia/Riyadh Asia/Saigon Asia/Sakhalin
Asia/Samarkand Asia/Seoul Asia/Shanghai Asia/Singapore Asia/Taipei
Asia/Tashkent Asia/Tbilisi Asia/Tehran Asia/Tel_Aviv Asia/Thimbu
Asia/Thimphu Asia/Tokyo Asia/Ujung_Pandang Asia/Ulaanbaatar Asia/Ulan_Bator
Asia/Urumqi Asia/Vientiane Asia/Vladivostok Asia/Yakutsk Asia/Yekaterinburg
Asia/Yerevan        
 
Atlantic
Atlantic/Azores Atlantic/Bermuda Atlantic/Canary Atlantic/Cape_Verde Atlantic/Faeroe
Atlantic/Faroe Atlantic/Jan_Mayen Atlantic/Madeira Atlantic/Reykjavik Atlantic/South_Georgia
Atlantic/St_Helena Atlantic/Stanley      
 
Australia
Australia/ACT Australia/Adelaide Australia/Brisbane Australia/Broken_Hill Australia/Canberra
Australia/Currie Australia/Darwin Australia/Eucla Australia/Hobart Australia/LHI
Australia/Lindeman Australia/Lord_Howe Australia/Melbourne Australia/North Australia/NSW
Australia/Perth Australia/Queensland Australia/South Australia/Sydney Australia/Tasmania
Australia/Victoria Australia/West Australia/Yancowinna    
 
Europe
Europe/Amsterdam Europe/Andorra Europe/Athens Europe/Belfast Europe/Belgrade
Europe/Berlin Europe/Bratislava Europe/Brussels Europe/Bucharest Europe/Budapest
Europe/Chisinau Europe/Copenhagen Europe/Dublin Europe/Gibraltar Europe/Guernsey
Europe/Helsinki Europe/Isle_of_Man Europe/Istanbul Europe/Jersey Europe/Kaliningrad
Europe/Kiev Europe/Lisbon Europe/Ljubljana Europe/London Europe/Luxembourg
Europe/Madrid Europe/Malta Europe/Mariehamn Europe/Minsk Europe/Monaco
Europe/Moscow Europe/Nicosia Europe/Oslo Europe/Paris Europe/Podgorica
Europe/Prague Europe/Riga Europe/Rome Europe/Samara Europe/San_Marino
Europe/Sarajevo Europe/Simferopol Europe/Skopje Europe/Sofia Europe/Stockholm
Europe/Tallinn Europe/Tirane Europe/Tiraspol Europe/Uzhgorod Europe/Vaduz
Europe/Vatican Europe/Vienna Europe/Vilnius Europe/Volgograd Europe/Warsaw
Europe/Zagreb Europe/Zaporozhye Europe/Zurich    
 
Indian
Indian/Antananarivo Indian/Chagos Indian/Christmas Indian/Cocos Indian/Comoro
Indian/Kerguelen Indian/Mahe Indian/Maldives Indian/Mauritius Indian/Mayotte
Indian/Reunion        
 
Pacific
Pacific/Apia Pacific/Auckland Pacific/Chatham Pacific/Easter Pacific/Efate
Pacific/Enderbury Pacific/Fakaofo Pacific/Fiji Pacific/Funafuti Pacific/Galapagos
Pacific/Gambier Pacific/Guadalcanal Pacific/Guam Pacific/Honolulu Pacific/Johnston
Pacific/Kiritimati Pacific/Kosrae Pacific/Kwajalein Pacific/Majuro Pacific/Marquesas
Pacific/Midway Pacific/Nauru Pacific/Niue Pacific/Norfolk Pacific/Noumea
Pacific/Pago_Pago Pacific/Palau Pacific/Pitcairn Pacific/Ponape Pacific/Port_Moresby
Pacific/Rarotonga Pacific/Saipan Pacific/Samoa Pacific/Tahiti Pacific/Tarawa
Pacific/Tongatapu Pacific/Truk Pacific/Wake Pacific/Wallis Pacific/Yap

source (http://php.net/manual/en/timezones.php)