diff --git a/docs/production/deployment.md b/docs/production/deployment.md
index 6fd286379c..60bc26218b 100644
--- a/docs/production/deployment.md
+++ b/docs/production/deployment.md
@@ -52,7 +52,8 @@ as well as those mentioned in the
 [install](install.md#installer-options) documentation:
 
 - `--postgresql-version`: Sets the version of PostgreSQL that will be
-  installed. We currently support PostgreSQL 12, 13, and 14.
+  installed. We currently support PostgreSQL 12, 13, 14, and 15, with 15 being
+  the default.
 
 - `--postgresql-database-name=exampledbname`: With this option, you
   can customize the default database name. If you do not set this. The
diff --git a/docs/production/postgresql.md b/docs/production/postgresql.md
index 48c0e56941..2e19a630d0 100644
--- a/docs/production/postgresql.md
+++ b/docs/production/postgresql.md
@@ -1,13 +1,13 @@
 # PostgreSQL database details
 
 Starting with Zulip 3.0, Zulip supports a range of PostgreSQL
-versions. PostgreSQL 14 is the current default for new installations;
-PostgreSQL 12, 13, and 14 are all supported.
+versions. PostgreSQL 15 is the current default for new installations;
+PostgreSQL 12, 13, 14, and 15 are all supported.
 
 Previous versions of Zulip used whatever version of PostgreSQL was
 included with the base operating system (E.g. PostgreSQL 12 on Ubuntu
 20.04). We recommend that installations currently using older
-PostgreSQL releases [upgrade to PostgreSQL 14][upgrade-postgresql], as
+PostgreSQL releases [upgrade to PostgreSQL 15][upgrade-postgresql], as
 we may drop support for older PostgreSQL in a future release.
 
 [upgrade-postgresql]: upgrade.md#upgrading-postgresql
diff --git a/docs/production/upgrade.md b/docs/production/upgrade.md
index 01a0ee6a33..b4f22ad543 100644
--- a/docs/production/upgrade.md
+++ b/docs/production/upgrade.md
@@ -618,9 +618,9 @@ instructions for other supported platforms.
 ## Upgrading PostgreSQL
 
 Starting with Zulip 3.0, we use the latest available version of
-PostgreSQL at installation time (currently version 14). Upgrades to
+PostgreSQL at installation time (currently version 15). Upgrades to
 the version of PostgreSQL are no longer linked to upgrades of the
-distribution; that is, you may opt to upgrade to PostgreSQL 14 while
+distribution; that is, you may opt to upgrade to PostgreSQL 15 while
 running Ubuntu 20.04.
 
 To upgrade the version of PostgreSQL on the Zulip server:
diff --git a/puppet/zulip/manifests/profile/postgresql.pp b/puppet/zulip/manifests/profile/postgresql.pp
index ce5bced65e..23f24b00f3 100644
--- a/puppet/zulip/manifests/profile/postgresql.pp
+++ b/puppet/zulip/manifests/profile/postgresql.pp
@@ -3,6 +3,7 @@ class zulip::profile::postgresql {
   include zulip::profile::base
   include zulip::postgresql_base
 
+  $version = $zulip::postgresql_common::version
   $work_mem = $zulip::common::total_memory_mb / 512
   $shared_buffers = $zulip::common::total_memory_mb / 8
   $effective_cache_size = $zulip::common::total_memory_mb * 10 / 32
@@ -29,14 +30,28 @@ class zulip::profile::postgresql {
     group  => 'postgres',
   }
 
-  $postgresql_conf_file = "${zulip::postgresql_base::postgresql_confdir}/postgresql.conf"
-  file { $postgresql_conf_file:
-    ensure  => file,
-    require => Package[$zulip::postgresql_base::postgresql],
-    owner   => 'postgres',
-    group   => 'postgres',
-    mode    => '0644',
-    content => template("zulip/postgresql/${zulip::postgresql_common::version}/postgresql.conf.template.erb"),
+  if $version in ['12','13','14'] {
+    $postgresql_conf_file = "${zulip::postgresql_base::postgresql_confdir}/postgresql.conf"
+    file { $postgresql_conf_file:
+      ensure  => file,
+      require => Package[$zulip::postgresql_base::postgresql],
+      owner   => 'postgres',
+      group   => 'postgres',
+      mode    => '0644',
+      content => template("zulip/postgresql/${version}/postgresql.conf.template.erb"),
+    }
+  } elsif $version in ['15'] {
+    $postgresql_conf_file = "${zulip::postgresql_base::postgresql_confdir}/conf.d/zulip.conf"
+    file { $postgresql_conf_file:
+      ensure  => file,
+      require => Package[$zulip::postgresql_base::postgresql],
+      owner   => 'postgres',
+      group   => 'postgres',
+      mode    => '0644',
+      content => template('zulip/postgresql/zulip.conf.template.erb'),
+    }
+  } else {
+    fail("PostgreSQL ${version} not supported")
   }
 
   if $replication_primary != '' and $replication_user != '' {
@@ -47,8 +62,7 @@ class zulip::profile::postgresql {
           |-EOT
       warning($message)
     }
-    # PostgreSQL uses the presence of a standby.signal file to trigger
-    # replication
+    # The presence of a standby.signal file triggers replication
     file { "${zulip::postgresql_base::postgresql_datadir}/standby.signal":
       ensure  => file,
       require => Package[$zulip::postgresql_base::postgresql],
@@ -57,11 +71,11 @@ class zulip::profile::postgresql {
       mode    => '0644',
       content => '',
     }
-  }
+    }
 
-  exec { $zulip::postgresql_base::postgresql_restart:
-    require     => Package[$zulip::postgresql_base::postgresql],
-    refreshonly => true,
-    subscribe   => [ File[$postgresql_conf_file] ],
-  }
+    exec { $zulip::postgresql_base::postgresql_restart:
+      require     => Package[$zulip::postgresql_base::postgresql],
+      refreshonly => true,
+      subscribe   => [ File[$postgresql_conf_file] ],
+    }
 }
diff --git a/puppet/zulip/templates/postgresql/zulip.conf.template.erb b/puppet/zulip/templates/postgresql/zulip.conf.template.erb
new file mode 100644
index 0000000000..bc196c3c55
--- /dev/null
+++ b/puppet/zulip/templates/postgresql/zulip.conf.template.erb
@@ -0,0 +1,63 @@
+<% if @listen_addresses != '' -%>
+# Bind to specific address
+listen_addresses = <%= @listen_addresses %>
+<% end -%>
+
+# This has an improved set of stopwords.
+default_text_search_config = 'zulip.english_us_search'
+
+# Provide more comprehensive on-disk logs
+logging_collector = on
+log_directory = '/var/log/postgresql'
+log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log'
+log_rotation_age = 7d
+log_rotation_size = 100MB
+log_min_duration_statement = 500
+log_line_prefix = '%m [%c]: [%l-1] '
+log_checkpoints = on
+log_lock_waits = on
+log_temp_files = 0
+log_autovacuum_min_duration = 100
+
+# Adjust autovacuum for having many mostly-append-only tables
+autovacuum_freeze_max_age = 2000000000
+vacuum_freeze_min_age     = 1000000000
+vacuum_freeze_table_age   = 1800000000
+
+# Performance settings
+max_connections = 1000
+maintenance_work_mem = <%= scope["zulip::profile::postgresql::maintenance_work_mem"] %>MB
+effective_cache_size = <%= scope["zulip::profile::postgresql::effective_cache_size"] %>MB
+work_mem = <%= scope["zulip::profile::postgresql::work_mem"] %>MB
+shared_buffers = <%= scope["zulip::profile::postgresql::shared_buffers"] %>MB
+wal_buffers = 4MB
+checkpoint_completion_target = 0.7
+<% if @random_page_cost != '' -%>
+random_page_cost = <%= @random_page_cost %>
+<% end -%>
+<% if @effective_io_concurrency != '' -%>
+effective_io_concurrency = <%= @effective_io_concurrency %>
+<% end -%>
+
+<% if @s3_backups_bucket != '' -%>
+# Streaming backups and replication
+archive_mode = on
+archive_command = '/usr/bin/timeout 10m /usr/local/bin/env-wal-g wal-push %p'
+restore_command = '/usr/local/bin/env-wal-g wal-fetch "%f" "%p"'
+<% if @replication_primary != '' && @replication_user != '' -%>
+primary_conninfo = 'host=<%= @replication_primary %> user=<%= @replication_user -%>
+<% if @replication_password != '' %> password=<%= @replication_password %><% end -%>
+<% if @ssl_mode != '' %> sslmode=<%= @ssl_mode %><% end -%>
+'
+<% end -%>
+<% end -%>
+
+<% if @ssl_cert_file != '' -%>
+ssl_cert_file = '<%= @ssl_cert_file %>'		# (change requires restart)
+<% end -%>
+<% if @ssl_key_file != '' -%>
+ssl_key_file = '<%= @ssl_key_file %>'		# (change requires restart)
+<% end -%>
+<% if @ssl_ca_file != '' -%>
+ssl_ca_file = '<%= @ssl_ca_file %>'		# (change requires restart)
+<% end -%>
diff --git a/scripts/lib/install b/scripts/lib/install
index 4b75a4027f..2aa4715aeb 100755
--- a/scripts/lib/install
+++ b/scripts/lib/install
@@ -32,7 +32,7 @@ Options:
       Sets the PostgreSQL database name.
   --postgresql-database-user=zulip
       Sets the PostgreSQL database user.
-  --postgresql-version=14
+  --postgresql-version=15
       Sets the version of PostgreSQL that will be installed.
   --postgresql-missing-dictionaries
       Set postgresql.missing_dictionaries, which alters the initial database.  Use with
@@ -140,7 +140,7 @@ read -r -a ADDITIONAL_PACKAGES <<<"${ADDITIONAL_PACKAGES:-}"
 # e.g. zulip::profile::app_frontend for a Zulip frontend server.
 PUPPET_CLASSES="${PUPPET_CLASSES:-zulip::profile::standalone}"
 VIRTUALENV_NEEDED="${VIRTUALENV_NEEDED:-yes}"
-POSTGRESQL_VERSION="${POSTGRESQL_VERSION:-14}"
+POSTGRESQL_VERSION="${POSTGRESQL_VERSION:-15}"
 
 if [ -n "$SELF_SIGNED_CERT" ] && [ -n "$USE_CERTBOT" ]; then
     set +x
diff --git a/scripts/setup/upgrade-postgresql b/scripts/setup/upgrade-postgresql
index 51a0f897d5..b103f0eb17 100755
--- a/scripts/setup/upgrade-postgresql
+++ b/scripts/setup/upgrade-postgresql
@@ -12,7 +12,7 @@ export LC_ALL=C.UTF-8
 export LANG=C.UTF-8
 export LANGUAGE=C.UTF-8
 
-UPGRADE_TO=${1:-14}
+UPGRADE_TO=${1:-15}
 UPGRADE_FROM=$(crudini --get /etc/zulip/zulip.conf postgresql version)
 ZULIP_PATH="$(dirname "$0")/../.."