Undecember — patch notes and updates
Stored observation / content update:
Dated developer announcements recorded from Steam. Open the source for the complete update.
| Update | Date | Excerpt / source |
|---|---|---|
| May.14 (Thu) Advance Notice of Darkness Energy Removal | 2026-04-30 | Greetings, Rune Hunters. As previously announced, on the update of May 14, 2026 (Thu), and related items will be removed. Please refer to the details below. ※ The information may change when the update takes place. \ We hope the information above will help you avoid any inconvenience as you play the game. Thank you. |
| Advance Notice on Upcoming Changes with May.14 Update | 2026-04-30 | Greetings, Rune Hunters. There will be various changes coming into effect with the new update that is taking place on May.14(Thu). Among them, advance notice is provided regarding the reset contents, the end of Season , and some content adjustments in preparation for the new season update. ※ The information may change when the update takes place. \ We hope the information above will help you avoid any inconvenience as you play the game. Thank you. |
| [Completed] Apr. 23 Scheduled Maintenance | 2026-04-22 | Greetings, Rune Hunters. We would like to inform you that UNDECEMBER will undergo scheduled maintenance on Apr. 23 (Thu) to provide even more reliable game services. Please see below for more details on the maintenance schedule. 1. Maintenance Schedule : Apr. 23 (Thu) 08:00 ~ 12:00 10:17 (UTC+9) 2. Maintenance Details \ 3. To Note ■ The maintenance schedule may change depending on circumstances. ■ Gameplay will be unavailable during maintenance, so please exit the game in a safe zone before maintenance begins. ■ Please note that you will not be able to enter the Abyss Gate, Auction House, Constellation of Time, Arena, Chaos Dungeons, and Euno |
| New Season Pre-celebration Event Notice | 2026-04-13 | Greetings, Rune Hunters. Notice regarding the 'New Season Pre-celebration event' starting after Apr 9 (Thu). Please see below for more details. |
| Notice of Products Available for Sale After Apr.9 (Thu) | 2026-04-09 | Greetings, Rune Hunters. We would like to inform you about the new products that will be available for purchase after the update on Apr.9 (Thu). You can find detailed information about these products in the guide below or in the and sections within the game. We appreciate your attention to this information when using the Cash Shop. List of Products on Sale 1. New Product and Package Sales 2. Season New Age Zodiac Pass 4 Thank you. |
| [Completed] Apr.9 Scheduled Maintenance | 2026-04-07 | Greetings, Rune Hunters. We would like to inform you that UNDECEMBER will undergo scheduled maintenance on Apr.9 (Thu) to provide even more reliable game services. Please see below for more details on the maintenance schedule. 1. Maintenance Schedule : Apr.9 (Thu) 08:00 ~ 12:00 11:30 (UTC+9) 2. Maintenance Details \ 3. To Note ■ The maintenance schedule may change depending on circumstances. ■ Gameplay will be unavailable during maintenance, so please exit the game in a safe zone before maintenance begins. ■ Please note that you will not be able to enter the Abyss Gate, Auction House, Constellation of Time, Arena, Chaos Dungeons, and Eunos Du |
| Advance Notice on the End of Package and Product Sales | 2026-04-02 | Greetings, Rune Hunters. We would like to inform you in advance that certain packages and products currently on sale at the Shop will no longer be available after the following dates. Please see below for more details. We hope the information will help you avoid any inconvenience. Advance Notice on the End of Package and Product Sales 1. Ending Date - After Scheduled Maintenance on Apr 9, 2026 (Thu) 2. Products No Longer Sold from Apr 9, 2026 (Thu) 3. To Note ※ The package and products will be sold only until the above-mentioned date. ※ Except for Pass products, purchased products can be used normally even after the sales end. ※ Unused 2026 S |
| [Completed] Mar. 26 Scheduled Maintenance | 2026-03-24 | Greetings, Rune Hunters. We would like to inform you that UNDECEMBER will undergo scheduled maintenance on Mar. 26 (Thu) to provide even more reliable game services. Please see below for more details on the maintenance schedule. Mar. 26 Scheduled Maintenance 1. Maintenance Schedule : Mar. 26 (Thu) 08:00 - \12:30\ \10:41\ (UTC+9) 2. Maintenance Details \ 3. To Note ■ The maintenance schedule may change depending on circumstances. ■ Gameplay will be unavailable during maintenance, so please exit the game in a safe zone before maintenance begins. ■ Please note that you will not be able to enter the Abyss Gate, Auction House, Constellation of Tim |
| Mar. 12 Server Patch | 2026-03-12 | Greetings, Rune Hunters. UNDECEMBER will be undergoing a server patch on Mar. 12 (Thu) to address identified issues. Please refer to the following information for details. Mar. 12 Server Patch 1. Server Patch Schedule: Mar. 12 (Thu) 18:20 (UTC+9) * The server patch will proceed without maintenance. * The game will therefore be available to play while the server patch is underway. 2. Server Patch Details - Fixed an issue where the effect was not applied when equipping Unique Gear or Abyss Stone related to the Skill Rune . - Fixed an issue where the effect was not applied when equipping Unique Gear or Abyss Stone related to the Skill Rune . 3. |
| Undecember Welcome Spring Event | 2026-03-12 | Greetings, Rune Hunters. Welcome the warm spring with Undecember! A is here for our precious Rune Hunters. Please check the details below. 1. Spring Blossom Coin Exchange Shop Event 2. Spring Blossom Event Attendance |
| Notice of Events Taking Place After Mar. 12 (Thu) | 2026-03-12 | Greetings, Rune Hunters. We would like to inform you about the events that will take place after Mar. 12 (Thu). Please see below for more details. 1. UNDECEMBER Rock-Paper-Scissors Event 2. Total Playtime Event 3. Season New Age Hot Time Event (3rd) ※ The Hot Time event will only be available in Season Mode. |
| [Completed] Mar. 12 Scheduled Maintenance | 2026-03-10 | Greetings, Rune Hunters. Maintenance has been completed and UNDECEMBER is now available to play. Please see below for more details on the maintenance schedule. Mar. 12 Scheduled Maintenance 1. Maintenance Schedule : Mar 12, 08:00 ~ 12:30 11:50 (UTC+9) 2. Maintenance Details \ 3. To Note ■ The maintenance schedule may change depending on circumstances. ■ Gameplay will be unavailable during maintenance, so please exit the game in a safe zone before maintenance begins. ■ Please note that you will not be able to enter the Abyss Gate, Auction House, Constellation of Time, Arena, Chaos Dungeons, and Eunos Dungeons for 10 minutes before and after th |
| Advance Notice on the End of Package and Product Sales | 2026-03-05 | Greetings, Rune Hunters. We would like to inform you in advance that certain packages and products currently on sale at the Shop will no longer be available after the following dates. Please see below for more details. We hope the information will help you avoid any inconvenience. Advance Notice on the End of Package and Product Sales 1. Ending Date - After the Mar. 12 (Thu) scheduled maintenance 2. Products No Longer Sold from Mar. 12 (Thu) 3. To Note ※ The relevant packages and products will only be sold until the dates above. ※ Products you have already purchased, except for Pass products, can still be used normally even after the sale of |
| [Completed] Feb. 26 Scheduled Maintenance | 2026-02-24 | Greetings, Rune Hunters. We would like to inform you that UNDECEMBER will undergo scheduled maintenance on Feb. 26 (Thu) to provide even more reliable game services. Please see below for more details on the maintenance schedule. Feb. 26 Scheduled Maintenance 1. Maintenance Schedule : Feb. 26 (Thu) 07:00 - 12:00 (UTC+9) 2. Maintenance Details 3. To Note ■ The maintenance schedule may change depending on circumstances. ■ Gameplay will be unavailable during maintenance, so please exit the game in a safe zone before maintenance begins. ■ Please note that you will not be able to enter the Abyss Gate, Auction House, Constellation of Time, Arena, Ch |
| Advance Notice on the End of Package and Product Sales | 2026-02-20 | Greetings, Rune Hunters. We would like to inform you in advance that certain packages and products currently on sale at the Shop will no longer be available after the following dates. Please see below for more details. We hope the information will help you avoid any inconvenience. Advance Notice on the End of Package and Product Sales 1. Ending Date - After the Feb. 26 (Thu) scheduled maintenance 2. Products No Longer Sold from Feb. 26 (Thu) 3. To Note ※ The relevant packages and products will only be sold until the dates above. ※ Products you have already purchased, except for Pass products, can still be used normally even after the sale of |
| Notice of Events Taking Place After Feb. 12 (Thu) | 2026-02-12 | Greetings, Rune Hunters. We would like to inform you about the events that will take place after Feb. 12 (Thu). Please see below for more details. 1. Puru's Valentine's Day Gift Event 2. Total Playtime Event 3. Season New Age Hot Time Event Notice (2nd) |
| Notice of Products Available for Sale After Feb. 12 (Thu) | 2026-02-12 | Greetings, Rune Hunters. We would like to inform you about the new products that will be available for purchase after the update on Feb. 12 (Thu). You can find detailed information about these products in the guide below or in the and sections within the game. We appreciate your attention to this information when using the Cash Shop. List of Products on Sale 1. New Product and Package Sales 2. New Costume Shop Products and Packages 3. Season New Age Zodiac Pass 2 4. Gear Summon |
| UNDECEMBER Lunar New Year Event Guide | 2026-02-12 | Greetings, Rune Hunters. To celebrate the arrival of 2026, a Lunar New Year Event has been prepared for our valued Rune Hunters who continue their journey with UNDECEMBER. Please check the details below for more information. List of Upcoming Events 1. Lunar New Year Exchange Shop Event 2. Event Attendance 3. Abyss Gate Special Reward Event 4. Lunar New Year Total Playtime Event |
| [Completed] Feb. 12 Scheduled Maintenance | 2026-02-10 | Greetings, Rune Hunters. We would like to inform you that UNDECEMBER will undergo scheduled maintenance on Feb. 12 (Thu) to provide even more reliable game services. Please see below for more details on the maintenance schedule. Feb. 12 Scheduled Maintenance 1. Maintenance Schedule : Feb. 12 (Thu) 07:00 - 12:00 (UTC+9) 2. Maintenance Details 3. To Note ■ The maintenance schedule may change depending on circumstances. ■ Gameplay will be unavailable during maintenance, so please exit the game in a safe zone before maintenance begins. ■ Please note that you will not be able to enter the Abyss Gate, Auction House, Constellation of Time, Arena, Ch |
| Advance Notice on the End of Package and Product Sales | 2026-02-05 | Greetings, Rune Hunters. We would like to inform you in advance that certain packages and products currently on sale at the Shop will no longer be available after the following dates. Please see below for more details. We hope the information will help you avoid any inconvenience. Advance Notice on the End of Package and Product Sales 1. Ending Date - After the Feb. 12 (Thu) scheduled maintenance 2. Items Scheduled for Sale End on 02/12 (Thu) 3. To Note ※ The relevant packages and products will only be sold until the dates above. ※ Products you have already purchased, except for Pass products, can still be used normally even after the sale of |