diff --git a/.circleci/config.yml b/.circleci/config.yml
index 4351ad001..4ea7cc328 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -1,6 +1,6 @@
 # Tagging a commit with [circle front] will build the front page and perform test-doc.
 # Tagging a commit with [circle full] will build everything.
-version: 2
+version: 2.1
 jobs:
     build_docs:
       docker:
diff --git a/RELEASES.md b/RELEASES.md
index 063701229..98d226431 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -26,6 +26,7 @@
 - Fix mean centering in `ot.dr.fda` and `ot.dr.wda`: `np.mean(X)` returned a scalar instead of the per-feature mean, so `proj` did not center the data as documented. In `ot.dr.fda` the same pattern in the class means made the between-class scatter matrix independent of which features separate the classes, and FDA returned a non-discriminant direction (PR #840)
 - `ot.dr.fda` and `ot.dr.wda` no longer modify the input array `X` in place (PR #840)
 - Fix `UnbalancedSinkhornTransport` `transform` failing with `AttributeError: 'NoneType' object has no attribute 'array_equal'` when `fit` was called with missing parameters (PR #837, Issue #650)
+- Update CircleCI config to use `version: 2.1` instead of the deprecated `version: 2. --- IGNORE ---` (PR #882)
 
 ## 0.9.7.post1