+--- 1.6.26 2013/03/08
+
+New pz:metadata attribute, empty="empty-value" for Pazpar2's
+internal representation. With this attribute, Pazpar2 treates an empty
+pz:metadata type as having the value for "empty" - if empty.
+
+New setting, pz:extendrecs, which triggers extended fetch of records
+for a database beyond pz:maxrecs for a show command.
+
+Fix warning that was falsely issued for "missing limitmap".
+
+Log message for Pazpart start/stop changed. Now using same style as
+Metaproxy, ie Pazpar2 start SHA1 / Pazpar2 stop .
+
+--- 1.6.25 2013/02/07
+
+Fix hang of 2nd command=show with esn/syntax given.
+
+--- 1.6.24 2013/01/18
+
+New merge attribute type: 'first', which takes all metadata fields
+from first target that returns the particular field.
+
+--- 1.6.23 2013/01/02
+
+Extend info command with hostname and YAZ SHA1
+Indent results for both command stat and info.
+
+Allow limit on merged content. The new configuration metadata
+element, limitcluster, configures that a metadata element (name) be used
+as limit name for search. Applies to the whole service (ie all targets),
+unlike pz:limitmap which is configured per-target (database).
+
+New feature: limitmap local:* matches against all metadata fields.
+
+Allow repeated list in limitmap spec . Separated by comma. For
+example: value="local:title,rpn:@attr 1=4".
+
+New element <message> in bytarget response. Holds diagnostic message
+of code (say 'Unsupported Use Attribute' for Bib-1 114).
+
+Improved logging for record ingestion failures.
+
+Avoid using struct icu_chain in non-YAZ_HAVE_ICU mode. In the rare case,
+when YAZ is compiled without ICU support.
+
+--- 1.6.22 2012/10/11
+
+Requires YAZ-4.2.40 to support native solr support.
+
+Fix and improve logic handling whether or not to re-do search on sort
+order changes. A sort order with change in ascending/descending only
+whould not trigger a new search, which is required for targets with
+native sorting capabilities. Each client is now checked if instructions
+(sortmap) exist for native sorting and only client that does requires
+it is researched. Other clients is just re-ingesting the records,
+they already have. The resultset is now cleared if any researching
+is done.
+
+Connection sharing between session has broken since version 1.6.8 with
+introduction of logic that would minimize searching if pazpar2 could
+detect this based on same query and limits and partly sort order.
+This could lead to segementations violations.
+
+Added a chapter in the manaul about relevance ranking.
+
+--- 1.6.21 2012/09/24
+
+Rank tweak: follow=number will increase mult by number if two terms
+occur next to each other; number-1 if they are one term apart , .. 0
+if they are number a part (all in order). Default is 0 (following
+terms has no effect).
+
+Rank tweak: lead=k will divide mult by 1 + log2(1+k*l) where k is
+value given by lead and l is length from beginning of field where
+term occurs (l=0 for first term, l=1 for second term, ..). Default
+value of k is 0.0.
+
+Rank tweak: length=strategy. length="linear" if mult is to be divided
+by length (existing, default behavior), length="log" if mult is to be
+divided by log2(1+length), length="none" if mult is not to be affected
+by length.
+
+--- 1.6.20 2012/09/21
+
+Rank algorithm details may be printed as part of show response in
+element <relevance_info>.. This is only printed if <rank debug="yes"/>
+is used in service.
+
+Record as returned by show/record command have a minimal indentation
+which makes things human-readable.
+
+New configuration of default sorting criteria (sort-default) in
+service definition. If no criteria is defined it will be as before
+'relevance'.
+
+Search command now supports sort parameter just as the show command.
+If no parameter is give, it will use the service sort-default value.
+
+--- 1.6.19 2012/09/18
+
+Rank algorithm skips strings that gets normalized to empty string.
+For example, & and ! could map to the empty string. The weight for
+those terms is now 0 (as if they were not part of the query).
+
+Rank algorithm does not use CCL from limitmap; only from the query
+parameter (user query).
+
+Obey -w dir.
+
+--- 1.6.18 2012/09/17
+
+Rank algorithm configurable by 'rank' element inside service. So far
+only, attribute 'cluster' is recognized. If cluster="yes", multiple
+records inside a cluster boosts higher than single records. This
+is default behavior and existing behavior. cluster="no" takes the
+average score of each record in a cluster.
+