diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..9e0a135
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,90 @@
+name: CI
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+
+jobs:
+  test:
+    name: PG ${{ matrix.pg }} / PHP ${{ matrix.php }}
+    runs-on: ubuntu-24.04
+    strategy:
+      fail-fast: false
+      matrix:
+        # Every supported PostgreSQL against the distro PHP...
+        pg: [11, 12, 13, 14, 15, 16, 17, 18]
+        php: ["8.3"]
+        # ...plus the other supported PHP versions against the newest PG.
+        include:
+          - { pg: 18, php: "8.1" }
+          - { pg: 18, php: "8.2" }
+          - { pg: 18, php: "8.4" }
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Add the PGDG apt repository
+        run: |
+          sudo install -d /usr/share/postgresql-common/pgdg
+          sudo curl -fsSL https://www.postgresql.org/media/keys/ACCC4CF8.asc \
+            -o /usr/share/postgresql-common/pgdg/apt.postgresql.org.asc
+          echo "deb [signed-by=/usr/share/postgresql-common/pgdg/apt.postgresql.org.asc] http://apt.postgresql.org/pub/repos/apt $(lsb_release -cs)-pgdg main" \
+            | sudo tee /etc/apt/sources.list.d/pgdg.list
+
+      - name: Add the ondrej/php PPA (non-distro PHP versions)
+        if: matrix.php != '8.3'
+        run: sudo add-apt-repository -y ppa:ondrej/php
+
+      - name: Install PostgreSQL ${{ matrix.pg }} and PHP ${{ matrix.php }}
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y \
+            postgresql-${{ matrix.pg }} postgresql-server-dev-${{ matrix.pg }} \
+            php${{ matrix.php }}-dev libphp${{ matrix.php }}-embed php${{ matrix.php }}-xml
+          php-config${{ matrix.php }} --php-sapis | grep -q embed
+
+      - name: Build and install PL/php
+        run: |
+          make PG_CONFIG=/usr/lib/postgresql/${{ matrix.pg }}/bin/pg_config \
+               PHP_CONFIG=php-config${{ matrix.php }}
+          sudo make PG_CONFIG=/usr/lib/postgresql/${{ matrix.pg }}/bin/pg_config \
+               PHP_CONFIG=php-config${{ matrix.php }} install
+
+      - name: Build and install jsonb_plphp
+        run: |
+          make -C jsonb_plphp \
+               PG_CONFIG=/usr/lib/postgresql/${{ matrix.pg }}/bin/pg_config \
+               PHP_CONFIG=php-config${{ matrix.php }}
+          sudo make -C jsonb_plphp \
+               PG_CONFIG=/usr/lib/postgresql/${{ matrix.pg }}/bin/pg_config \
+               PHP_CONFIG=php-config${{ matrix.php }} install
+
+      - name: Start the cluster
+        run: |
+          # the runner image disables automatic cluster creation
+          sudo pg_createcluster ${{ matrix.pg }} main 2>/dev/null || true
+          sudo pg_ctlcluster ${{ matrix.pg }} main start
+          pg_lsclusters
+
+      - name: Run the regression tests
+        run: |
+          port=$(pg_lsclusters | awk '$1 == "${{ matrix.pg }}" && $2 == "main" { print $3 }')
+          # let the postgres user reach and write the workspace
+          sudo chmod a+x /home/runner /home/runner/work /home/runner/work/PL-php
+          chmod -R a+rwX .
+          sudo -u postgres env PGPORT=$port \
+            make PG_CONFIG=/usr/lib/postgresql/${{ matrix.pg }}/bin/pg_config installcheck
+
+      - name: Run the jsonb_plphp regression tests
+        run: |
+          port=$(pg_lsclusters | awk '$1 == "${{ matrix.pg }}" && $2 == "main" { print $3 }')
+          sudo -u postgres env PGPORT=$port \
+            make -C jsonb_plphp \
+                 PG_CONFIG=/usr/lib/postgresql/${{ matrix.pg }}/bin/pg_config installcheck
+
+      - name: Show regression diffs on failure
+        if: failure()
+        run: |
+          cat regression.diffs 2>/dev/null || true
+          cat jsonb_plphp/regression.diffs 2>/dev/null || true
diff --git a/CHANGELOG.md b/CHANGELOG.md
index ebc7d5c..6c72670 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,11 +9,24 @@ and the project aims to follow [Semantic Versioning](https://semver.org/).
 
 ### Added
 
+- **Continuous integration** — a GitHub Actions matrix building and running
+  the full regression suite (core + `jsonb_plphp`) on PostgreSQL 11-18 and
+  PHP 8.1/8.2/8.3/8.4 for every pull request.
 - **VARIADIC parameters.** A variadic function's collected arguments arrive
   as a single PHP array, matching every other PL (`VARIADIC "any"` remains
   unsupported and is rejected with a clear error). Previously any VARIADIC
   declaration failed.
 
+### Fixed
+
+- **PHP 8.1, 8.2, and 8.4 compatibility.** PL/php now builds and passes the
+  full suite on PHP 8.1 through 8.4: a version guard for the
+  `php_module_startup` signature change (8.2), explicit `fgetcsv` arguments
+  in the cookbook (8.4 deprecation), and a clear compile error below 8.1.
+  The Makefiles now prefer the `libphp` matching `PHP_CONFIG`'s version when
+  several are installed (see INSTALL for a packaging caveat about shared
+  SONAMEs).
+
 ## [2.2.0] — 2026-07-05
 
 ### Added
diff --git a/INSTALL b/INSTALL
index 7848e4f..06565ab 100644
--- a/INSTALL
+++ b/INSTALL
@@ -41,6 +41,12 @@ from PATH.  Override them if needed:
     make PG_CONFIG=/usr/lib/postgresql/18/bin/pg_config PHP_CONFIG=/usr/bin/php-config
     sudo make PG_CONFIG=/usr/lib/postgresql/18/bin/pg_config install
 
+Note: if several libphpX.Y-embed versions are installed side by side, some
+packagings (e.g. deb.sury.org) give them all the same SONAME (libphp.so), so
+the backend loads whatever /usr/lib/libphp.so points at -- regardless of the
+version linked at build time.  Keep a single embed package installed, or
+point that symlink at the intended version.
+
 This installs the shared library plphp.so plus the extension control and SQL
 files into the directories reported by pg_config.
 
diff --git a/Makefile b/Makefile
index 7c414b8..17c2122 100644
--- a/Makefile
+++ b/Makefile
@@ -22,7 +22,13 @@ DATA = plphp--2.2.sql plphp--2.0--2.1.sql plphp--2.1--2.2.sql
 PHP_CONFIG ?= php-config
 PHP_INCLUDES := $(shell $(PHP_CONFIG) --includes)
 PHP_LIBDIR := $(shell $(PHP_CONFIG) --prefix)/lib
-PHP_LIBNAME := $(patsubst lib%.so,%,$(notdir $(firstword $(wildcard $(PHP_LIBDIR)/libphp*.so /usr/lib/libphp*.so /usr/lib/*/libphp*.so))))
+# Prefer the library matching PHP_CONFIG's version (e.g. libphp8.3.so); with
+# several PHP versions installed, a bare "libphp*.so" glob would pick the
+# unversioned symlink of whichever version owns it.
+PHP_VERSION := $(shell $(PHP_CONFIG) --version | cut -d. -f1-2)
+PHP_LIBNAME := $(patsubst lib%.so,%,$(notdir $(firstword $(wildcard \
+	$(PHP_LIBDIR)/libphp$(PHP_VERSION).so /usr/lib/libphp$(PHP_VERSION).so /usr/lib/*/libphp$(PHP_VERSION).so \
+	$(PHP_LIBDIR)/libphp*.so /usr/lib/libphp*.so /usr/lib/*/libphp*.so))))
 
 PG_CPPFLAGS = $(PHP_INCLUDES)
 # Link against the PHP embed library only; its own transitive dependencies
diff --git a/README.md b/README.md
index 4ed4a16..6e29c2c 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@
 **Write PostgreSQL functions, triggers, and procedures in PHP.**
 
 [![PostgreSQL](https://img.shields.io/badge/PostgreSQL-11_to_18-336791?logo=postgresql&logoColor=white)](https://www.postgresql.org/)
-[![PHP](https://img.shields.io/badge/PHP-8.x-777BB4?logo=php&logoColor=white)](https://www.php.net/)
+[![PHP](https://img.shields.io/badge/PHP-8.1--8.4-777BB4?logo=php&logoColor=white)](https://www.php.net/)
 [![Tests](https://img.shields.io/badge/tests-17_passing-brightgreen)](sql/)
 [![License](https://img.shields.io/badge/license-permissive-blue)](#license)
 
@@ -99,7 +99,7 @@ $$;
 
 - **PostgreSQL 11 or newer** (tested on 11–18; 18 recommended), with the server
   development files that provide `pg_config`.
-- **PHP 8.x** built with the **embed SAPI** and **without** ZTS (thread safety).
+- **PHP 8.1 through 8.4** built with the **embed SAPI** and **without** ZTS (thread safety).
   On Debian/Ubuntu, install `php8.x-dev` and `libphp8.x-embed`.
 
 ## Installation
diff --git a/doc/cookbook.md b/doc/cookbook.md
index 3f472e0..07e94e9 100644
--- a/doc/cookbook.md
+++ b/doc/cookbook.md
@@ -216,7 +216,7 @@ LANGUAGE plphp STRICT AS $$
     $fh = fopen($args[0], "r");
     if ($fh === false)
         pg_raise('error', "cannot open {$args[0]}");
-    while (($rec = fgetcsv($fh)) !== false)
+    while (($rec = fgetcsv($fh, null, ",", "\"", "\\")) !== false)
         return_next($rec);
     fclose($fh);
     return;
diff --git a/doc/plphp.md b/doc/plphp.md
index 7a5d51f..a6acb90 100644
--- a/doc/plphp.md
+++ b/doc/plphp.md
@@ -4,8 +4,8 @@ PL/php lets you write PostgreSQL functions and triggers in PHP. This document
 describes the programming interface. For build and install instructions see
 [`INSTALL`](../INSTALL); for a feature summary see [`README`](../README.md).
 
-Tested on **PostgreSQL 11 through 18** with **PHP 8.3** (embed SAPI,
-non-thread-safe).
+Tested on **PostgreSQL 11 through 18** with **PHP 8.1 through 8.4** (embed
+SAPI, non-thread-safe).
 
 - [Enabling the language](#enabling-the-language)
 - [Writing functions](#writing-functions)
diff --git a/expected/cookbook.out b/expected/cookbook.out
index 421597d..b43f0b8 100644
--- a/expected/cookbook.out
+++ b/expected/cookbook.out
@@ -216,7 +216,7 @@ LANGUAGE plphp STRICT AS $$
     $fh = fopen($args[0], "r");
     if ($fh === false)
         pg_raise('error', "cannot open {$args[0]}");
-    while (($rec = fgetcsv($fh)) !== false)
+    while (($rec = fgetcsv($fh, null, ",", "\"", "\\")) !== false)
         return_next($rec);
     fclose($fh);
     return;
diff --git a/jsonb_plphp/Makefile b/jsonb_plphp/Makefile
index d783b78..4192c0a 100644
--- a/jsonb_plphp/Makefile
+++ b/jsonb_plphp/Makefile
@@ -16,7 +16,13 @@ DATA = jsonb_plphp--1.0.sql
 PHP_CONFIG ?= php-config
 PHP_INCLUDES := $(shell $(PHP_CONFIG) --includes)
 PHP_LIBDIR := $(shell $(PHP_CONFIG) --prefix)/lib
-PHP_LIBNAME := $(patsubst lib%.so,%,$(notdir $(firstword $(wildcard $(PHP_LIBDIR)/libphp*.so /usr/lib/libphp*.so /usr/lib/*/libphp*.so))))
+# Prefer the library matching PHP_CONFIG's version (e.g. libphp8.3.so); with
+# several PHP versions installed, a bare "libphp*.so" glob would pick the
+# unversioned symlink of whichever version owns it.
+PHP_VERSION := $(shell $(PHP_CONFIG) --version | cut -d. -f1-2)
+PHP_LIBNAME := $(patsubst lib%.so,%,$(notdir $(firstword $(wildcard \
+	$(PHP_LIBDIR)/libphp$(PHP_VERSION).so /usr/lib/libphp$(PHP_VERSION).so /usr/lib/*/libphp$(PHP_VERSION).so \
+	$(PHP_LIBDIR)/libphp*.so /usr/lib/libphp*.so /usr/lib/*/libphp*.so))))
 
 PG_CPPFLAGS = $(PHP_INCLUDES)
 SHLIB_LINK = -L$(PHP_LIBDIR) -l$(PHP_LIBNAME) $(shell $(PHP_CONFIG) --ldflags)
diff --git a/plphp.c b/plphp.c
index 010d04c..c74eb30 100644
--- a/plphp.c
+++ b/plphp.c
@@ -76,6 +76,10 @@
 /* PHP stuff */
 #include "php.h"
 
+#if PHP_VERSION_ID < 80100
+#error "PL/php requires PHP 8.1 or newer (zend_error_cb signature)"
+#endif
+
 #include "php_variables.h"
 #include "php_globals.h"
 #include "zend_hash.h"
@@ -413,9 +417,11 @@ plphp_init_all(void)
 		plphp_init();
 
 	/*
-	 * Any other initialization that must be done each time a new
-	 * backend starts -- currently none.
+	 * Loaded PHP extensions can swap zend_error_cb behind our back at any
+	 * point; put ours back before running anything.  It is a plain pointer
+	 * assignment, so doing it on every call is free.
 	 */
+	zend_error_cb = plphp_error_cb;
 }
 
 /*
@@ -450,8 +456,14 @@ plphp_init(void)
 			plphp_sapi_module.phpinfo_as_text = 1;
 			sapi_startup(&plphp_sapi_module);
 
+#if PHP_VERSION_ID >= 80200
 			if (php_module_startup(&plphp_sapi_module, NULL) == FAILURE)
 				elog(ERROR, "php_module_startup call failed");
+#else
+			/* PHP 8.1 still took an additional-modules count */
+			if (php_module_startup(&plphp_sapi_module, NULL, 0) == FAILURE)
+				elog(ERROR, "php_module_startup call failed");
+#endif
 
 			/* php_module_startup changed it, so put it back */
 			zend_error_cb = plphp_error_cb;
@@ -476,6 +488,22 @@ plphp_init(void)
 			INI_HARDCODED("max_execution_time", "0");
 			INI_HARDCODED("max_input_time", "-1");
 
+			/*
+			 * The host's php.ini must not decide which errors reach our
+			 * zend_error_cb, or how they are routed: force full reporting
+			 * and disable opcache/JIT, which add nothing for our one-shot
+			 * eval'd functions and can interfere with error delivery.
+			 * (GitHub's runner images, for example, ship a PHP configured
+			 * with opcache+JIT enabled for CLI, which broke both notices
+			 * and error messages.)
+			 */
+			INI_HARDCODED("error_reporting", "32767");	/* E_ALL */
+			INI_HARDCODED("display_errors", "0");
+			INI_HARDCODED("log_errors", "0");
+			INI_HARDCODED("opcache.enable", "0");
+			INI_HARDCODED("opcache.enable_cli", "0");
+			INI_HARDCODED("xdebug.mode", "off");
+
 			/*
 			 * Set memory limit to ridiculously high value.  This helps the
 			 * server not to crash, because the PHP allocator has the really
@@ -504,6 +532,13 @@ plphp_init(void)
 
 			PG(during_request_startup) = true;
 
+			/*
+			 * Extensions loaded from the host's php.ini (xdebug, for one)
+			 * may have hooked zend_error_cb during module or request
+			 * startup; ours must be the one in place.
+			 */
+			zend_error_cb = plphp_error_cb;
+
 			/*
 			 * Register our SPI functions and the procedure cache now that the
 			 * request (and its interned-string tables) is fully initialized.
diff --git a/sql/cookbook.sql b/sql/cookbook.sql
index f13ced7..899126d 100644
--- a/sql/cookbook.sql
+++ b/sql/cookbook.sql
@@ -156,7 +156,7 @@ LANGUAGE plphp STRICT AS $$
     $fh = fopen($args[0], "r");
     if ($fh === false)
         pg_raise('error', "cannot open {$args[0]}");
-    while (($rec = fgetcsv($fh)) !== false)
+    while (($rec = fgetcsv($fh, null, ",", "\"", "\\")) !== false)
         return_next($rec);
     fclose($fh);
     return;