add correct release version in comment

src/client-cohttp-eio/opentelemetry_client_cohttp_eio.mli

@@ -18,7 +18,7 @@ val create_backend :
   (module Opentelemetry.Collector.BACKEND)
 (** Create a new backend using Cohttp_eio
 
-    NOTE [after_cleanup] optional parameter removed since NEXT_RELEASE *)
+    NOTE [after_cleanup] optional parameter removed @since 0.12 *)
 
 val setup :
   ?stop:bool Atomic.t ->
@@ -38,7 +38,7 @@ val setup :
 
 val remove_backend : unit -> unit
 (** Shutdown current backend
-    @since NEXT_RELEASE *)
+    @since 0.12 *)
 
 val with_setup :
   ?stop:bool Atomic.t ->

src/client-cohttp-lwt/opentelemetry_client_cohttp_lwt.mli

@@ -19,7 +19,7 @@ val create_backend :
   (module Opentelemetry.Collector.BACKEND)
 (** Create a new backend using lwt and cohttp
 
-    NOTE [after_cleanup] optional parameter removed since NEXT_RELEASE *)
+    NOTE [after_cleanup] optional parameter removed @since 0.12 *)
 
 val setup :
   ?stop:bool Atomic.t -> ?config:Config.t -> ?enable:bool -> unit -> unit
@@ -34,7 +34,7 @@ val setup :
 
 val remove_backend : unit -> unit Lwt.t
 (** Shutdown current backend
-    @since NEXT_RELEASE *)
+    @since 0.12 *)
 
 val with_setup :
   ?stop:bool Atomic.t ->

src/client-ocurl/config.mli

@@ -14,7 +14,7 @@ type t = {
           @since 0.7 *)
   common: Opentelemetry_client.Config.t;
       (** Common configuration options
-          @since NEXT_RELEASE*)
+          @since 0.12*)
 }
 (** Configuration.
 

src/client-ocurl/opentelemetry_client_ocurl.mli

@@ -29,7 +29,7 @@ val setup :
       after a little while. *)
 
 val remove_backend : unit -> unit
-(** @since NEXT_RELEASE *)
+(** @since 0.12 *)
 
 val with_setup :
   ?stop:bool Atomic.t ->

src/core/opentelemetry.ml

@@ -93,7 +93,7 @@ module Collector = struct
     (** [cleanup ~on_done ()] is called when the collector is shut down, and is
         responsible for sending remaining batches, flushing sockets, etc.
         @param on_done
-          callback invoked after the cleanup is done. since NEXT_RELEASE *)
+          callback invoked after the cleanup is done. @since 0.12 *)
   end
 
   type backend = (module BACKEND)
@@ -178,7 +178,7 @@ module Collector = struct
 
   (** Remove current backend, if any.
       @since 0.11
-      @param on_done see {!BACKEND.cleanup}, since NEXT_RELEASE *)
+      @param on_done see {!BACKEND.cleanup}, @since 0.12 *)
   let remove_backend ~on_done () : unit =
     match Atomic.exchange backend None with
     | None -> ()
@@ -688,7 +688,7 @@ module Globals = struct
   let service_instance_id = ref None
 
   (** Version for the service
-      @since NEXT_RELEASE *)
+      @since 0.12 *)
   let service_version = ref None
 
   let instrumentation_library =