# Best practices to update Trellis

**URL:** https://discourse.roots.io/t/best-practices-to-update-trellis/5386
**Category:** trellis
**Created:** 2015-12-01T16:24:39Z
**Posts:** 46
**Showing post:** 31 of 46

## Post 31 by @runofthemill — 2016-07-29T22:30:42Z

FYI - if anyone is using this method and getting this error message:

```
fatal: refusing to merge unrelated histories
```

it’s because the default changed in git 2.9; see [this SO](http://stackoverflow.com/questions/37937984/git-refusing-to-merge-unrelated-histories) question.

Add `--allow-unrelated-histories` to make the command work again:

```
git merge -X subtree=trellis/ --squash trellis/master --allow-unrelated-histories
```

:slight_smile:

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