[[breaking_70_indices_changes]]
=== Indices changes

==== `:` is no longer allowed in index name

Due to cross-cluster search using `:` to separate a cluster and index name,
index names may no longer contain `:`.

==== `index.unassigned.node_left.delayed_timeout` may no longer be negative

Negative values were interpreted as zero in earlier versions but are no
longer accepted.


==== `_flush` and `_force_merge` will no longer refresh

In previous versions issuing a `_flush` or `_force_merge` (with `flush=true`)
had the undocumented side-effect of refreshing the index which made new documents
visible to searches and non-realtime GET operations. From now on these operations
don't have this side-effect anymore. To make documents visible an explicit `_refresh`
call is needed unless the index is refreshed by the internal scheduler.