[#2142] Remove references to outdated Kea versions

15 files changed, 96 insertions, 180 deletions

diff --git a/doc/sphinx/arm/admin.rst b/doc/sphinx/arm/admin.rst
index 1be290f58d..0a801bbca8 100644
--- a/doc/sphinx/arm/admin.rst
+++ b/doc/sphinx/arm/admin.rst
@@ -66,12 +66,6 @@ currently supported commands are:
    meant to be used as a diagnostic tool, so it provides a portable,
    human-readable form of the lease data.
 
-.. note::
-
-  In versions of Kea earlier than 1.6.0, the ``db-init``, ``db-version``, and
-  ``db-upgrade`` commands were named ``lease-init``, ``lease-version``, and
-  ``lease-upgrade``, respectively.
-
 ``backend`` specifies the type of backend database. The currently
 supported types are:
 
diff --git a/doc/sphinx/arm/config-backend.rst b/doc/sphinx/arm/config-backend.rst
index ca882ec699..92249bf3ee 100644
--- a/doc/sphinx/arm/config-backend.rst
+++ b/doc/sphinx/arm/config-backend.rst
@@ -8,8 +8,7 @@ Kea Configuration Backend
 Applicability
 -------------
 
-Kea Configuration Backend (CB or config backend) is a feature, first
-introduced in Kea 1.6.0, that gives Kea servers the ability
+Kea Configuration Backend (CB or config backend) gives Kea servers the ability
 to manage and fetch their configuration from one or more databases. In
 this documentation, the term "Configuration Backend" may also refer to
 the particular Kea module providing support to manage and fetch the
@@ -155,7 +154,6 @@ in two independent configuration sources.
 CB Components
 -------------
 
-Kea 1.6.0 version or later is required to use the configuration backend.
 The ``mysql_cb`` open source hook library implementing the configuration
 backend for MySQL must be compiled and loaded by the DHCP servers. This
 hook library is compiled when the ``--with-mysql`` configuration switch
diff --git a/doc/sphinx/arm/config.rst b/doc/sphinx/arm/config.rst
index d21fb671cc..e578f982b0 100644
--- a/doc/sphinx/arm/config.rst
+++ b/doc/sphinx/arm/config.rst
@@ -91,19 +91,6 @@ A very simple configuration for DHCPv4 could look like this:
 More examples are available in the installed ``share/doc/kea/examples``
 directory.
 
- .. note::
-
-   As of Kea 1.6.0, the "Logging" element was removed and its contents (the
-   "loggers" object) moved inside the configuration objects (maps) for the
-   respective Kea modules. For example, the "Dhcp4" map contains the
-   "loggers" object, specifying logging configuration for the DHCPv4
-   server. Support for the top-level "Logging" object was
-   removed in Kea 1.7.10.
-
-   The specification for supporting several elements (e.g. "Dhcp4", "Dhcp6")
-   in one file was removed in Kea 1.7.10, so each component
-   now requires a separate configuration file.
-
 To avoid repetition of mostly similar structures, examples in the rest
 of this guide will showcase only the subset of parameters appropriate
 for a given context. For example, when discussing the IPv6 subnets
diff --git a/doc/sphinx/arm/dhcp4-srv.rst b/doc/sphinx/arm/dhcp4-srv.rst
index ccd2c03406..2798c0a371 100644
--- a/doc/sphinx/arm/dhcp4-srv.rst
+++ b/doc/sphinx/arm/dhcp4-srv.rst
@@ -146,14 +146,6 @@ curly bracket (or brace). Each configuration must contain an object
 specifying the configuration of the Kea module using it. In the example
 above, this object is called ``Dhcp4``.
 
-.. note::
-
-   In the current Kea release it is still possible to specify configurations
-   of multiple modules within a single configuration file, but this is
-   not recommended; support for this was removed in Kea 1.7.10,
-   including the ``Logging`` object. Its previous content, the list
-   of loggers, must now be inside the ``Dhcp4`` object.
-
 The ``Dhcp4`` configuration starts with the ``"Dhcp4": {`` line and ends
 with the corresponding closing brace (in the above example, the brace
 after the last comment). Everything defined between those lines is
@@ -184,8 +176,8 @@ client begins the renewal and rebind processes.
 
 .. note::
 
-   Beginning with Kea 1.6.0, the lease valid-lifetime is extended from a
-   single value to a triplet with minimum, default, and maximum values using
+   The lease valid lifetime is expressed as a triplet with minimum, default, and
+   maximum values using configuration entries
    ``min-valid-lifetime``, ``valid-lifetime``, and ``max-valid-lifetime``.
    Since Kea 1.9.5, these values may be specified in client classes. The procedure
    the server uses to select which lifetime value to use is as follows:
@@ -1519,7 +1511,7 @@ Care should be taken to use proper encoding when using hexadecimal
 format; Kea's ability to validate data correctness in hexadecimal is
 limited.
 
-Since Kea 1.6.0, it is also possible to specify data for binary options as
+It is also possible to specify data for binary options as
 a single-quoted text string within double quotes as shown (note that
 ``csv-format`` must be set to ``false``):
 
@@ -3046,9 +3038,7 @@ NCRs. Each NCR contains the following information:
 3. The Fully Qualified Domain Name (FQDN), lease address, and DHCID
    (information identifying the client associated with the FQDN).
 
-Prior to Kea 1.7.1, all parameters for controlling DDNS were within the
-global ``dhcp-ddns`` section of ``kea-dhcp4``.  Beginning with Kea 1.7.1,
-DDNS-related parameters were split into two groups:
+DDNS-related parameters are split into two groups:
 
 1. Connectivity Parameters
 
@@ -3128,7 +3118,7 @@ The default configuration and values would appear as follows:
         ...
    }
 
-Since Kea 1.7.1, there are two parameters which determine if ``kea-dhcp4``
+There are two parameters which determine if ``kea-dhcp4``
 can generate DDNS requests to D2: the existing ``dhcp-ddns:enable-updates``
 parameter, which now only controls whether ``kea-dhcp4`` connects to D2;
 and the new behavioral parameter, ``ddns-send-updates``, which determines
@@ -3225,9 +3215,9 @@ For NCRs to reach the D2 server, ``kea-dhcp4`` must be able to communicate
 with it. ``kea-dhcp4`` uses the following configuration parameters to
 control this communication:
 
--  ``enable-updates`` - Since Kea 1.7.1, this parameter only enables
-   connectivity to ``kea-dhcp-ddns`` such that DDNS updates can be constructed
-   and sent. It must be ``true`` for NCRs to be generated and sent to D2.
+-  ``enable-updates`` - Enables connectivity to ``kea-dhcp-ddns`` such that DDNS
+   updates can be constructed and sent.
+   It must be ``true`` for NCRs to be generated and sent to D2.
    It defaults to ``false``.
 
 -  ``server-ip`` - This is the IP address on which D2 listens for requests. The
@@ -3504,23 +3494,16 @@ and "-". This may be accomplished with the following two parameters:
    character set. This can be any valid, regular expression using POSIX
    extended expression syntax. Embedded nulls (0x00) are always
    considered an invalid character to be replaced (or omitted).
+   The default is ``"[^A-Za-z0-9.-]"``. This matches any character that is not
+   a letter, digit, dot, hyphen, or null.
 
 -  ``hostname-char-replacement`` - a string of zero or more characters
    with which to replace each invalid character in the host name. An empty
    string causes invalid characters to be OMITTED rather than replaced.
-
-.. note::
-
-    Since Kea 1.7.5, the default values are as follows:
-
-    - "hostname-char-set": "[^A-Za-z0-9.-]",
-    - "hostname-char-replacement": ""
-
-    This enables sanitizing and omits any character that is not
-    a letter, digit, hyphen, dot, or null.
+   The default is ``""``.
 
 The following configuration replaces anything other than a letter,
-digit, hyphen, or dot with the letter "x":
+digit, dot, or hyphen with the letter "x":
 ::
 
     "Dhcp4": {
@@ -3568,7 +3551,7 @@ qualifying suffix (if one is defined and needed).
 
 .. note::
 
-   Since the 1.6.0 Kea release, it is possible to specify ``hostname-char-set``
+   It is possible to specify ``hostname-char-set``
    and/or ``hostname-char-replacement`` at the global scope. This allows
    host names to be sanitized without requiring a ``dhcp-ddns`` entry. When
    a ``hostname-char`` parameter is defined at both the global scope and
@@ -3833,7 +3816,7 @@ configuration of the DHCPv4 side (the DHCPv6 side is described in
 
    DHCPv4-over-DHCPv6 support is experimental and the details of the
    inter-process communication may change; for instance, the
-   support of port relay (RFC 8357) in Kea 1.4.0 introduced an incompatible change.
+   support of port relay (RFC 8357) introduced an incompatible change.
    Both the DHCPv4 and DHCPv6 sides should be running the same version of Kea.
 
 The ``dhcp4o6-port`` global parameter specifies the first of the two
@@ -4208,8 +4191,7 @@ DHCPv4 message such as ``siaddr``, ``sname``, or ``file``.
 
 .. note::
 
-   Kea versions 1.7.10 and newer require that the reserved address must
-   be within the subnet.
+   The reserved address must be within the subnet.
 
 The following example shows how to reserve addresses for specific hosts
 in a subnet:
@@ -5951,9 +5933,7 @@ configurations, e.g. shared networks. See :ref:`dhcp4-relay-override` for detail
 
 .. note::
 
-   Starting with Kea 1.7.9, the order used to find a subnet which matches
-   required conditions to be selected is the ascending subnet identifier
-   order. When the selected subnet is a member of a shared network, the
+   When the selected subnet is a member of a shared network, the
    whole shared network is selected.
 
 .. _dhcp4-relay-override:
@@ -6598,8 +6578,8 @@ The DHCPv4 server supports the following statistics:
    This section describes DHCPv4-specific statistics. For a general
    overview and usage of statistics, see :ref:`stats`.
 
-Since Kea 1.7.7, the DHCPv4 server provides two global
-parameters to control statistics default sample limits:
+The DHCPv4 server provides two global parameters to control default sample
+limits of statistics:
 
 - ``statistic-default-sample-count`` - determines the default maximum
   number of samples which are kept. The special value of 0
@@ -7097,8 +7077,7 @@ default value of ``config-fetch-wait-time`` is 30 seconds.
 
 The ``config-backend-pull`` command can be used to force the server to
 immediately poll any configuration changes from the database and avoid
-waiting for the next fetch cycle. (This command was added in Kea version
-1.7.1 for both DHCPv4 and DHCPv6 servers.)
+waiting for the next fetch cycle.
 
 Finally, in the configuration example above, two hook libraries are
 loaded. The first, ``libdhcp_mysql_cb.so``, is the implementation of
diff --git a/doc/sphinx/arm/dhcp6-srv.rst b/doc/sphinx/arm/dhcp6-srv.rst
index 1fcbbf4655..f4673a8c7f 100644
--- a/doc/sphinx/arm/dhcp6-srv.rst
+++ b/doc/sphinx/arm/dhcp6-srv.rst
@@ -147,14 +147,6 @@ curly bracket (or brace). Each configuration must contain an object
 specifying the configuration of the Kea module using it. In the example
 above, this object is called ``Dhcp6``.
 
-.. note::
-
-   In the current Kea release it is still possible to specify configurations
-   of multiple modules within a single configuration file, but this is
-   not recommended; support for this was removed in Kea 1.7.10,
-   including the ``Logging`` object. Its previous content, the list
-   of loggers, must now be inside the ``Dhcp6`` object.
-
 The ``Dhcp6`` configuration starts with the ``"Dhcp6": {`` line and ends
 with the corresponding closing brace (in the above example, the brace
 after the last comment). Everything defined between those lines is
@@ -1233,9 +1225,9 @@ Care should be taken to use proper encoding when using hexadecimal
 format; Kea's ability to validate data correctness in hexadecimal is
 limited.
 
-Since Kea 1.6.0, it is also possible to specify data for binary options as
+It is also possible to specify data for binary options as
 a single-quoted text string within double quotes, as shown (note that
-``csv-format`` must be set to false):
+``csv-format`` must be set to ``false``):
 
 ::
 
@@ -2260,9 +2252,8 @@ specified explicitly or that are calculated as percentages of the
 preferred lease time. The server's behavior is determined by a combination
 of configuration parameters, of which T1 and T2 are only two.
 
-Since Kea 1.6.0, the lease's preferred and valid lifetimes are extended from
-single values to triplets with minimum, default, and maximum values, with
-the following settings:
+The lease's preferred and valid lifetimes are expressed as triplets with
+minimum, default, and maximum values using configuration entries:
 
 - ``min-preferred-lifetime`` - specifies the minimum preferred lifetime (optional).
 
@@ -2727,9 +2718,7 @@ NCR contains the following information:
 3. The Fully Qualified Domain Name (FQDN), lease address, and DHCID
    (information identifying the client associated with the FQDN).
 
-Prior to Kea 1.7.1, all parameters for controlling DDNS were within the
-global ``dhcp-ddns`` section of ``kea-dhcp6``. Beginning with Kea 1.7.1,
-DDNS-related parameters were split into two groups:
+DDNS-related parameters are split into two groups:
 
 1. Connectivity Parameters
 
@@ -2809,7 +2798,7 @@ The default configuration and values would appear as follows:
         ...
    }
 
-Since Kea 1.7.1, there are two parameters which determine if ``kea-dhcp6``
+There are two parameters which determine if ``kea-dhcp6``
 can generate DDNS requests to D2: the existing ``dhcp-ddns:enable-updates``
 parameter, which now only controls whether ``kea-dhcp6`` connects to D2;
 and the new behavioral parameter, ``ddns-send-updates``, which determines
@@ -2906,9 +2895,8 @@ For NCRs to reach the D2 server, ``kea-dhcp6`` must be able to communicate
 with it. ``kea-dhcp6`` uses the following configuration parameters to
 control this communication:
 
--  ``enable-updates`` - Since Kea 1.7.1, this parameter only enables
-   connectivity to ``kea-dhcp-ddns`` such that DDNS updates can be constructed
-   and sent. It must be ``true`` for NCRs to be generated and sent to D2.
+-  ``enable-updates`` - Enables connectivity to ``kea-dhcp-ddns`` such that DDNS
+   updates can be constructed and sent. It must be ``true`` for NCRs to be generated and sent to D2.
    It defaults to "false".
 
 -  ``server-ip`` - This is the IP address on which D2 listens for requests. The
@@ -3193,23 +3181,16 @@ accomplished with the following two parameters:
    character set. This can be any valid, regular expression using POSIX
    extended expression syntax. Embedded nulls (0x00) are always
    considered an invalid character to be replaced (or omitted).
+   The default is ``"[^A-Za-z0-9.-]"``. This matches any character that is not
+   a letter, digit, dot, hyphen, or null.
 
 -  ``hostname-char-replacement`` - a string of zero or more characters
    with which to replace each invalid character in the host name. An empty
    string causes invalid characters to be OMITTED rather than replaced.
-
-.. note::
-
-    Since Kea 1.7.5, the default values are as follows:
-
-    - "hostname-char-set": "[^A-Za-z0-9.-]",
-    - "hostname-char-replacement": ""
-
-    This enables sanitizing and omits any character that is not
-    a letter, digit, hyphen, dot, or null.
+   The default is ``""``.
 
 The following configuration replaces anything other than a letter,
-digit, hyphen, or dot with the letter "x":
+digit, dot, or hyphen with the letter "x":
 ::
 
     "Dhcp6": {
@@ -3253,7 +3234,7 @@ qualifying suffix (if one is defined and needed).
 
 .. note::
 
-   Since the 1.6.0 Kea release, it is possible to specify ``hostname-char-set``
+   It is possible to specify ``hostname-char-set``
    and/or ``hostname-char-replacement`` at the global scope. This allows
    host names to be sanitized without requiring a ``dhcp-ddns`` entry. When
    a ``hostname-char`` parameter is defined at both the global scope and
@@ -3637,8 +3618,8 @@ specify a hostname and DHCPv6 options for a given host.
 
 .. note::
 
-   Kea versions 1.7.10 and newer require that the reserved address must
-   be within the subnet. This does not apply to reserved prefixes.
+   The reserved address must be within the subnet.
+   This does not apply to reserved prefixes.
 
 The following example shows how to reserve addresses and prefixes for
 specific hosts:
@@ -5626,9 +5607,7 @@ relays.
 
 .. note::
 
-   Since Kea 1.7.9, subnets are matched with
-   required conditions in ascending subnet identifier
-   order. When the selected subnet is a member of a shared network, the
+   When the selected subnet is a member of a shared network, the
    whole shared network is selected.
 
 A relay must have an interface connected to the link on which the
@@ -6524,8 +6503,8 @@ The DHCPv6 server supports the following statistics:
    This section describes DHCPv6-specific statistics. For a general
    overview and usage of statistics, see :ref:`stats`.
 
-Since Kea 1.7.7, the DHCPv6 server provides two global
-parameters to control statistics default sample limits:
+The DHCPv6 server provides two global parameters to control default sample
+limits of statistics:
 
 - ``statistic-default-sample-count`` - determines the default maximum
   number of samples which are kept. The special value of 0
diff --git a/doc/sphinx/arm/hammer.rst b/doc/sphinx/arm/hammer.rst
index 6f1ff58231..a8b8c8bcef 100644
--- a/doc/sphinx/arm/hammer.rst
+++ b/doc/sphinx/arm/hammer.rst
@@ -3,8 +3,7 @@
 Hammer Building Tool
 ====================
 
-An optional building tool called Hammer was introduced with Kea 1.6.0. It
-is a Python 3 script that lets users automate tasks related to building
+Hammer is a Python 3 script that lets users automate tasks related to building
 Kea, such as setting up virtual machines, installing Kea dependencies,
 compiling Kea with various options, running unit-tests and more. This
 tool was created primarily for internal QA purposes at ISC and it is not
diff --git a/doc/sphinx/arm/hooks-bootp.rst b/doc/sphinx/arm/hooks-bootp.rst
index cd4356099a..01cfeff350 100644
--- a/doc/sphinx/arm/hooks-bootp.rst
+++ b/doc/sphinx/arm/hooks-bootp.rst
@@ -14,7 +14,7 @@ The DHCP-specific options, such as ``dhcp-message-type``, are removed from
 the server's responses; responses shorter than the BOOTP minimum
 size of 300 octets are padded to this size.
 
-This open source library has been available since Kea 1.7.2. It is loaded
+This open source library is loaded
 similarly to other hook libraries by the ``kea-dhcp4`` process, and
 it takes no parameters.
 
diff --git a/doc/sphinx/arm/hooks-ha.rst b/doc/sphinx/arm/hooks-ha.rst
index 66a6722ce5..6d6c8f00b8 100644
--- a/doc/sphinx/arm/hooks-ha.rst
+++ b/doc/sphinx/arm/hooks-ha.rst
@@ -107,14 +107,12 @@ load-balancing and hot-standby setup, in addition to the active servers.
 There is no limit on the number of backup servers in the HA setup;
 however, the presence of backup servers may increase the latency
 of DHCP responses, because not only do active servers send lease updates
-to each other, but also to the backup servers. Since Kea 1.7.8, the active
-servers no longer expect acknowledgments from the backup servers
+to each other, but also to the backup servers. The active
+servers don't expect acknowledgments from the backup servers
 before responding to the DHCP clients, so the overhead of sending
-lease updates to the backup servers is minimized compared to
-earlier Kea versions.
+lease updates to the backup servers is minimized.
 
-The last supported configuration, ``passive-backup``, was introduced
-in Kea 1.7.8. In this configuration, there is only one active
+The last supported configuration, ``passive-backup``, there is only one active
 server and typically one or more backup servers. A passive-backup
 configuration with no backup servers is also accepted, but it is no
 different than running a single server with no HA function at all.
@@ -129,8 +127,8 @@ backup servers to provide DHCP service to the clients, as these
 servers should have accurate or nearly accurate information about the
 allocated leases. The major advantage of the passive-backup mode is that
 it provides some redundancy of the lease information but with better
-performance of the primary server responding to the DHCP queries. Since
-Kea 1.7.8, the primary server does not have to wait for
+performance of the primary server responding to the DHCP queries.
+The primary server does not have to wait for
 acknowledgments to the lease updates from the backup servers before it
 sends a response to the DHCP client. This reduces the response time
 compared to the load-balancing and hot-standby cases, in which the
@@ -181,17 +179,14 @@ clocks and restart the servers.
 
 .. note::
 
-   Prior to Kea 1.7.8, the administrator had to shut down both servers
-   and then restart both of them to recover from the terminated state.
-   Since Kea 1.7.8, it is possible to restart the
-   servers one at a time, in sequence. The clocks must be in sync
-   before restarting the servers.
+   It is possible to restart the servers one at a time, in no particular oder.
+   The clocks must be in sync before restarting the servers.
 
 .. note::
 
    The clock skew is only assessed between two active servers, and
    only the active servers enter the ``terminated`` state if the skew is
-   too high. Since Kea 1.7.8, clock skew between active and
+   too high. The clock skew between active and
    backup servers is not assessed, because active servers do
    not exchange heartbeat messages with backup servers.
 
@@ -1606,7 +1601,7 @@ and four threads for the client.
 
    It is essential to configure the ports correctly. One common mistake
    is to configure CA to listen on port 8000 and also configure dedicated listeners on port
-   8000. In such a configuration, the DHCP server will fail to bind sockets, but the communication
+   1.    In such a configuration, the DHCP server will fail to bind sockets, but the communication
    will still work via CA, albeit slowly. Make sure your dedicated listeners use a different port
    (8001 is a suggested alternative). If you misconfigure ports or use the ports used by CA, the
    performance bottlenecks caused by the single-threaded nature of CA and the sequential nature of
@@ -1749,7 +1744,6 @@ and allowing it to complete its normal state negotiation process.
 Upgrading from Older HA Versions
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-The HA maintenance mechanism was first introduced in the Kea 1.7.4 release.
 To upgrade from an older HA hook library to the current version, the
 administrator must shut down one of the servers and rely on the
 failover mechanism to force the online server to transition to the
@@ -2049,14 +2043,6 @@ the HA status of two load-balancing servers:
 The ``high-availability`` argument is a list which currently comprises
 only one element.
 
-.. note::
-
-   In Kea 1.7.8 an incompatible change was introduced to the syntax of the
-   ``status-get`` response. Previously, the HA status for a single relationship
-   was returned within the ``arguments`` map. As of Kea 1.7.8, the returned status
-   is enclosed in the list as described above. Any existing code relying on the
-   previous syntax must be updated to work with newer Kea versions.
-
 The ``ha-servers`` map contains two structures: ``local`` and ``remote``. The former
 contains the status information of the server which received the command, while the
 latter contains the status information known to the local server about the
@@ -2089,8 +2075,8 @@ responding to this traffic. More about the failover procedure can be found
 in :ref:`ha-load-balancing-config`.
 
 The ``connecting-clients``, ``unacked-clients``, ``unacked-clients-left``,
-and ``analyzed-packets`` parameters were introduced with the
-``communication-interrupted`` parameter in Kea 1.7.8; they
+and ``analyzed-packets`` parameters were introduced along with the
+``communication-interrupted`` parameter and they
 convey useful information about the state of the DHCP traffic monitoring
 in the ``communication-interrupted`` state. Once the server leaves the
 ``communication-interrupted`` state, these parameters are all reset to 0.
@@ -2123,8 +2109,7 @@ Monitoring these values helps to predict when the local server will
 enter the ``partner-down`` state or to understand why the server has not yet entered this
 state.
 
-The last parameter introduced in Kea 1.7.8 was ``ha-mode``.
-It returns the HA mode of operation selected using the ``mode`` parameter
+The ``ha-mode`` parameter returns the HA mode of operation selected using the ``mode`` parameter
 in the configuration file. It can hold one of the following values:
 ``load-balancing``, ``hot-standby``, or ``passive-backup``.
 
diff --git a/doc/sphinx/arm/hooks-lease-cmds.rst b/doc/sphinx/arm/hooks-lease-cmds.rst
index 84cded3640..ce45c9d78e 100644
--- a/doc/sphinx/arm/hooks-lease-cmds.rst
+++ b/doc/sphinx/arm/hooks-lease-cmds.rst
@@ -803,9 +803,9 @@ An example IPv4 lease deletion by ``"hw-address"`` is:
    }
 
 
-Since Kea 1.7.10, a new parameter, ``update-ddns``, is supported (IPv4 and IPv6).
-When ``true``, it instructs the server to queue a request to ``kea-dhcp-ddns`` to
-remove DNS entries after the lease is successfully deleted if:
+Another parameter called ``update-ddns``, when ``true``, instructs the server to
+queue a request to ``kea-dhcp-ddns`` to remove DNS entries after the lease is
+successfully deleted if:
 
 - DDNS updating is enabled (i.e. ``"dhcp-ddns":{ "enable-updates": true }``).
 - The lease's hostname is not empty.
diff --git a/doc/sphinx/arm/hooks-radius.rst b/doc/sphinx/arm/hooks-radius.rst
index 74c4c037d3..95eeacb162 100644
--- a/doc/sphinx/arm/hooks-radius.rst
+++ b/doc/sphinx/arm/hooks-radius.rst
@@ -50,8 +50,8 @@ on CentOS 7.0. Other systems may differ slightly.
 
 .. note::
 
-   Since Kea 1.7.0, ISC provides Kea software and hooks in convenient-to-use
-   native DEB and RPM packages. This includes the RADIUS hook and the required patched version
+   ISC provides Kea software and hooks in convenient-to-use
+   native Alpine, deb and RPM packages. This includes the RADIUS hook and the required patched version
    of the FreeRADIUS client library. The software compilation for RADIUS is complicated; unless
    there are specific reasons to compile it, administrators should seriously consider using
    native packages.
@@ -120,8 +120,8 @@ Note that the ``b2`` script may optionally take extra parameters; one of
 them specifies the destination path where the sources are to be
 compiled.
 
-Alternatively, some systems provide newer Boost packages. For example, 
-CentOS 7 provides ``boost169-devel``. If it is installed with 
+Alternatively, some systems provide newer Boost packages. For example,
+CentOS 7 provides ``boost169-devel``. If it is installed with
 ``yum install boost169-devel``, Kea must be pointed to it with:
 
 .. code-block:: console
diff --git a/doc/sphinx/arm/hooks.rst b/doc/sphinx/arm/hooks.rst
index 7efd3965c7..10a9af74fb 100644
--- a/doc/sphinx/arm/hooks.rst
+++ b/doc/sphinx/arm/hooks.rst
@@ -36,7 +36,7 @@ for specifics.
 When a Kea process unloads a library, it expects the ``dlclose`` function
 to remove all library symbols, as well as the library code, from address space.
 Although most OSes implement the ``dlclose`` function, this behavior is not
-required by the POSIX standard and not all systems support it; for example, the musl 
+required by the POSIX standard and not all systems support it; for example, the musl
 library, used by default by Alpine Linux, implements the ``dlclose`` function
 as a no operation. On such systems a library actually remains loaded for the
 lifetime of the process, which means that it must be restarted
@@ -214,15 +214,7 @@ configuration would be:
 
 .. note::
 
-   This syntax is effective as of Kea 1.1.0, to facilitate the
-   specification of library-specific parameters. Libraries should allow a
-   parameter entry for comments, as is the case with many configuration
-   scopes.
-
-.. note::
-
-   In all versions of Kea since 1.1.0, libraries
-   are reloaded even if their lists have not changed,
+   Libraries are reloaded even if their lists have not changed,
    because the parameters specified for the library (or the files those
    parameters point to) may have changed.
 
@@ -1852,21 +1844,30 @@ contract.
    This library can only be loaded by the ``kea-dhcp4`` or ``kea-dhcp6``
    process.
 
-Currently, six commands are supported: ``reservation-add``, which adds a new
-host reservation; ``reservation-get``, which returns an existing reservation
-if specified criteria are matched; ``reservation-get-all``, which returns
-all reservations in a specified subnet; ``reservation-get-page``, a variant
-of ``reservation-get-all`` that returns all reservations in a specified
-subnet by pages (and, since Kea version 1.9.0, all reservations);
-``reservation-get-by-hostname``, which returns all reservations
-with a specified hostname and optionally in a subnet; since Kea version
-1.7.1, ``reservation-get-by-id``, which returns all reservations with a
-specified identifier since Kea version 1.9.0;
-and ``reservation-del``, which attempts to delete a
-reservation matching specified criteria. To use the commands that change
-reservation information (i.e. ``reservation-add`` and
-``reservation-del``), the hosts database must be specified and it must not operate
-in read-only mode (for details, see
+Currently, the following commands are supported:
+
+- ``reservation-add``, which adds a new host reservation
+
+- ``reservation-get``, which returns an existing reservation if specified
+  criteria are matched
+
+- ``reservation-get-all``, which returns all reservations in a specified subnet
+
+- ``reservation-get-page``, a variant of ``reservation-get-all`` that returns
+  reservations by pages, either all or in a specified subnet
+
+- ``reservation-get-by-hostname``, which returns all reservations with a
+  specified hostname and optionally in a subnet
+
+- ``reservation-get-by-id``, which returns all reservations with a specified
+  identifier since Kea version 1.9.0
+
+- ``reservation-del``, which attempts to delete a reservation matching specified
+  criteria.
+
+To use the commands that change reservation information
+(i.e. ``reservation-add`` and ``reservation-del``), the hosts database must be
+specified and it must not operate in read-only mode (for details, see
 the ``hosts-databases`` descriptions in :ref:`hosts-databases-configuration4`
 and :ref:`hosts-databases-configuration6`). If the ``hosts-databases`` are not specified or are
 running in read-only mode, the ``host_cmds`` library will load, but any
@@ -2313,8 +2314,7 @@ retrieve all reservations with a specified hostname or in
 a specified subnet. This command uses parameters providing the mandatory
 ``hostname`` and the optional ``subnet-id``. Global host reservations
 can be retrieved by using a ``subnet-id`` value of zero (0).
-Hostname matching is case-insensitive. This command is available since
-Kea version 1.7.1.
+Hostname matching is case-insensitive.
 
 For instance, retrieving host reservations for "foobar" in the subnet 1:
 
@@ -3473,9 +3473,7 @@ useful if administrators want their comments to survive ``config-set`` or ``conf
 operations, for example.
 
 If user context is supported in a given context, the parser translates
-"comment" entries into user context with a "comment" entry. The pretty
-print of a configuration did the opposite operation and put "comment"
-entries at the beginning of maps, but this was withdrawn in 1.7.9.
+"comment" entries into user context with a "comment" entry.
 
 Kea supports user contexts at the following levels: global scope,
 interfaces configuration, shared networks,
diff --git a/doc/sphinx/arm/install.rst b/doc/sphinx/arm/install.rst
index 5bef3a4248..1103c4a0df 100644
--- a/doc/sphinx/arm/install.rst
+++ b/doc/sphinx/arm/install.rst
@@ -631,15 +631,14 @@ and 1548). Be sure to replace ``ens4`` with the specific interface name.
 Deprecated Features
 ===================
 
-This section lists significant features that have been or will be removed. We try to 
+This section lists significant features that have been or will be removed. We try to
 deprecate features before removing them to signal
 to current users to plan a migration. New users should not rely on deprecated features.
 
 Cassandra (CQL) Support
 -----------------------
 
-Cassandra is a non-relational NoSQL database. Kea added support for the CQL lease backend in
-Kea 1.1.0-beta1 and the CQL host backend in 1.4.0-beta1. This feature never gained much
+Cassandra is a non-relational NoSQL database. This feature never gained much
 traction with users, particularly compared to the level of interest in and deployments of
 the alternatives, MySQL and PostgreSQL.
 
diff --git a/doc/sphinx/arm/keactrl.rst b/doc/sphinx/arm/keactrl.rst
index b9a6e87aeb..c5e6b3ceee 100644
--- a/doc/sphinx/arm/keactrl.rst
+++ b/doc/sphinx/arm/keactrl.rst
@@ -230,8 +230,8 @@ valid, uses the new configuration. A reload is executed as follows:
    INFO/keactrl: Reloading kea-ctrl-agent...
 
 If any of the servers are not running, an informational message is
-displayed as in the ``reload`` command output below. As of
-version 1.5.0, ``kea-netconf`` does not support the SIGHUP signal. If its
+displayed as in the ``reload`` command output below.
+``kea-netconf`` does not support the SIGHUP signal. If its
 configuration has changed, please stop and restart it for the change to
 take effect.
 
diff --git a/doc/sphinx/arm/logging.rst b/doc/sphinx/arm/logging.rst
index 77c431d0a6..57627cf391 100644
--- a/doc/sphinx/arm/logging.rst
+++ b/doc/sphinx/arm/logging.rst
@@ -16,8 +16,7 @@ can be safely ignored in a typical deployment. They are, however, very
 useful when debugging a problem.
 
 The logging system in Kea is configured through the ``loggers`` entry in the
-server section of the configuration file (Kea releases prior to 1.7.9 included this
-as an independent Logging section).
+server section of the configuration file.
 
 Loggers
 -------
diff --git a/doc/sphinx/arm/quickstart.rst b/doc/sphinx/arm/quickstart.rst
index 01cfd98044..40465351bd 100644
--- a/doc/sphinx/arm/quickstart.rst
+++ b/doc/sphinx/arm/quickstart.rst
@@ -51,10 +51,9 @@ Quick Start Guide Using tarball
 Quick Start Guide Using Native Packages
 =======================================
 
-As of Kea 1.6.0, ISC provides native RPM, deb, and APK
-packages, which make Kea installation much easier. Unless
-specific compilation options are desired, it is usually easier to install
-Kea using native packages.
+ISC provides native Alpine, deb and RPM packages, which make Kea installation
+much easier. Unless specific compilation options are desired, it is usually
+easier to install Kea using native packages.
 
 1. Go to `Kea on cloudsmith.io <https://cloudsmith.io/~isc/repos/>`__,
    choose the Kea version, and enter the repository.