Trello to Planner migration limitations

Considering to make a move from Trello to Planner? Below is a list of the limitations that you might face. 
Trello and Planner are very similar, yet quite different at the same time. There is handful of features that Trello has, that are rather limited in Planner.

  1. Files with the same name:
    • Trello allows importing several files with the same name into the board. Since files in Planner reside in the Sharepoint site of the underlying M365 group, this is not possible. In order not to miss any files, Altosio will rename these files with a numbered suffix if it detects duplicates. For example, if you have multiple files with the name “image.png” in Trello, the migration tool will push the first file as “image.png”, then the second file as “image-1.png”, the third file as “image-2.png” and so on. This will allow us to avoid the Sharepoint error “A file with the same name already exists”.
  2. Files with special characters:
    • Trello accepts special characters in the attached files, whereas Planner (Sharepoint to be specific) does not accept this set of characters (# % * : < > ? \ |) . Altosio will rename these files before migrating them and will remove these special characters.
  3. Maximum Planner plans:
    • In Trello, boards belong to workspaces. In M365, Planners belong to M365 Groups. Though you can have a Trello workspace having multiple boards, it is unfortunately not possible for an M365 group to host more than one Planner. Therefore, each Planner will belong to a separate Group (or Team).
  4. Multiple checklists in one card:
    • Trello allows the user to create multiple checklists in one single card. This is not possible using Planner. Planner allows one single checklist per task. The Altosio tool will, by default, migrate only the first checklist it finds in the card and will ignore the rest.
  5. Maximum Planner buckets:
    • There is no known limitation in Trello that says that you must have less than x number of lists in your Board. Since these lists are migrated as Planner buckets, there is a limitation of 200 buckets per Planner in M365. It is very unlikely to hit this limitation.
  6. Maximum tasks in a Planner:
    • Microsoft Planner does not allow more than 9000 tasks per Planner. It is very unlikely to hit this limitation, but it is something to consider.
  7. Maximum assignees in a task:
    • Trello does not have any limitation on how many people join a Trello card. Microsoft Planner does not allow more than 11 assignees on each task. If you have a card with more than 11 users joined to it, Altosio will pick up the first 10 and assign them to the target Planner task.
  8. Maximum Checklist items in a task:
    • Trello does not have a limit as to how many items can be under a checklist. This is limited in Planner to 20. If you have a Trello card that has a checklist that has more than 20 items, Altosio will pick up only the first 20 items and will ignore the rest.
  9. Maximum references on a task:
    • Trello allows having an unlimited number of files referenced on a card. Planner, on the other hand, can have only 10 references (to files or websites) on each task. Altosio will always pick up the first 10 references and ignore the rest if any. Please note that the actual files are still migrated. Only the extra references will be missed.
  10. Tasks metadata:
    • Microsoft does not provide any APIs that allow preserving the metatada of tasks. The tasks created with Altosio will always show as created by the migration account, at the time of the migration. (rather than the actual creation time of the card in Trello).
  11. Comments on cards:
    • Microsoft does not provide any APIs allowing the creation of comments with their real date-time and creator.  During the migration, Altosio will preserve this metadata by adding the name of the sender and the real date-time to the comment. The comment will appear as posted by the migration account at the time of the migration.
  12. Length of reference alias:
    • When adding a reference to a Planner task, the display name of that reference that appears on the task should not exceed 100 characters. If a reference in your Trello task exceeds that limit, Altosio will take the first 100 characters by default.
  13. Maximum length of a checklist item:
    • A checklist item length in Planner cannot exceed 100 characters. If you have a checklist item in a card exceeding that limit, Altosio will truncate it and will only take the first 100 characters.
  14. Card activities:
    • You can track card activities on Trello. This feature is not available on Microsoft Planner. Card activies will be lost after migration.

For more information, please visit this Microsoft documentation,  or contact us at