diff --git a/lib/platform/bitbucket-server/index.spec.ts b/lib/platform/bitbucket-server/index.spec.ts
index b0a4b7c3afaa4861b03e24a1fd572c99614d17b4..a80fa31192efbfc0c463b367e86d57e9ee9c78c0 100644
--- a/lib/platform/bitbucket-server/index.spec.ts
+++ b/lib/platform/bitbucket-server/index.spec.ts
@@ -157,11 +157,65 @@ describe('platform/bitbucket-server', () => {
       });
 
       describe('repoForceRebase()', () => {
-        it('always return false, since bitbucket does not support force rebase', async () => {
+        it('returns false on missing mergeConfig', async () => {
           expect.assertions(1);
+          api.get.mockResolvedValueOnce({
+            body: {
+              mergeConfig: null,
+            },
+          } as any);
           const actual = await bitbucket.getRepoForceRebase();
           expect(actual).toBe(false);
         });
+
+        it('returns false on missing defaultStrategy', async () => {
+          expect.assertions(1);
+          api.get.mockResolvedValueOnce({
+            body: {
+              mergeConfig: {
+                defaultStrategy: null,
+              },
+            },
+          } as any);
+          const actual = await bitbucket.getRepoForceRebase();
+          expect(actual).toBe(false);
+        });
+
+        it.each(['ff-only', 'rebase-ff-only', 'squash-ff-only'])(
+          'return true if %s strategy is enabled',
+          async id => {
+            expect.assertions(1);
+            api.get.mockResolvedValueOnce({
+              body: {
+                mergeConfig: {
+                  defaultStrategy: {
+                    id,
+                  },
+                },
+              },
+            } as any);
+            const actual = await bitbucket.getRepoForceRebase();
+            expect(actual).toBe(true);
+          }
+        );
+
+        it.each(['no-ff', 'ff', 'rebase-no-ff', 'squash'])(
+          'return false if %s strategy is enabled',
+          async id => {
+            expect.assertions(1);
+            api.get.mockResolvedValueOnce({
+              body: {
+                mergeConfig: {
+                  defaultStrategy: {
+                    id,
+                  },
+                },
+              },
+            } as any);
+            const actual = await bitbucket.getRepoForceRebase();
+            expect(actual).toBe(false);
+          }
+        );
       });
 
       describe('setBaseBranch()', () => {
diff --git a/lib/platform/bitbucket-server/index.ts b/lib/platform/bitbucket-server/index.ts
index eac03fb1caa89a1ca2fb510080fb5ca0d9a8b82e..7b93d1917be690d1b3baa36e3d81786d26b42657 100644
--- a/lib/platform/bitbucket-server/index.ts
+++ b/lib/platform/bitbucket-server/index.ts
@@ -234,13 +234,23 @@ export async function initRepo({
   }
 }
 
-export function getRepoForceRebase(): Promise<boolean> {
+export async function getRepoForceRebase(): Promise<boolean> {
   logger.debug(`getRepoForceRebase()`);
-  // TODO if applicable
-  // This function should return true only if the user has enabled a setting on the repo that enforces PRs to be kept up to date with master
-  // In such cases we rebase Renovate branches every time they fall behind
-  // In GitHub this is part of "branch protection"
-  return Promise.resolve(false);
+
+  // https://docs.atlassian.com/bitbucket-server/rest/7.0.1/bitbucket-rest.html#idp342
+  const res = await api.get(
+    `./rest/api/1.0/projects/${config.projectKey}/repos/${config.repositorySlug}/settings/pull-requests`
+  );
+
+  // If the default merge strategy contains `ff-only` the PR can only be merged
+  // if it is up to date with the base branch.
+  // The current options for id are:
+  // no-ff, ff, ff-only, rebase-no-ff, rebase-ff-only, squash, squash-ff-only
+  return Boolean(
+    res.body.mergeConfig &&
+      res.body.mergeConfig.defaultStrategy &&
+      res.body.mergeConfig.defaultStrategy.id.indexOf('ff-only') >= 0
+  );
 }
 
 export async function setBaseBranch(