diff --git a/CHANGELOG.md b/CHANGELOG.md
index 798321e3..a4e68bbc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,11 +3,11 @@
 ## [Unreleased]
 ### Added
 - `IMGPROXY_FALLBACK_IMAGE_HTTP_CODE` config.
-- [expires](https://docs.imgproxy.net/#/generating_the_url?id=expires) processing option.
-- [skip processing](https://docs.imgproxy.net/#/generating_the_url?id=skip-processing) processing option.
+- [expires](https://docs.imgproxy.net/generating_the_url?id=expires) processing option.
+- [skip processing](https://docs.imgproxy.net/generating_the_url?id=skip-processing) processing option.
 - [Datadog](./docs/datadog.md) metrics.
 - `force` and `fill-down` resizing types.
-- [min-width](https://docs.imgproxy.net/#/generating_the_url?id=min-width) and [min-height](https://docs.imgproxy.net/#/generating_the_url?id=min-height) processing options.
+- [min-width](https://docs.imgproxy.net/generating_the_url?id=min-width) and [min-height](https://docs.imgproxy.net/generating_the_url?id=min-height) processing options.
 
 ### Removed
 - Removed basic URL format, use [advanced one](./docs/generating_the_url.md) instead.
@@ -17,6 +17,14 @@
 - Removed `crop` resizing type, use [crop](./docs/generating_the_url.md#crop) processing option instead.
 - Dropped old libvips (<8.8) support.
 
+## [2.16.4] - 2021-06-16
+### Change
+- Use magenta (ff00ff) as a transparency key in `trim`.
+
+### Fix
+- Fix crashes while processing some SVGs (dockerized version).
+- (pro) Fix parsing HEIF/AVIF meta.
+
 ## [2.16.3] - 2021-04-05
 ### Fix
 - Fix PNG quantization palette size.
@@ -37,11 +45,11 @@
 ### Added
 - AVIF support.
 - Azure Blob Storage support.
-- `IMGPROXY_STRIP_COLOR_PROFILE` config and [strip_color_profile](https://docs.imgproxy.net/#/generating_the_url?id=strip-color-profile) processing option.
+- `IMGPROXY_STRIP_COLOR_PROFILE` config and [strip_color_profile](https://docs.imgproxy.net/generating_the_url?id=strip-color-profile) processing option.
 - `IMGPROXY_FORMAT_QUALITY` config.
-- `IMGPROXY_AUTO_ROTATE` config and [auto_rotate](https://docs.imgproxy.net/#/generating_the_url?id=auto-rotate) processing option.
-- [rotate](https://docs.imgproxy.net/#/generating_the_url?id=rotate) processing option.
-- `width` and `height` arguments of the [crop](https://docs.imgproxy.net/#/generating_the_url?id=crop) processing option can be less than `1` that is treated by imgproxy as a relative value (a.k.a. crop by percentage).
+- `IMGPROXY_AUTO_ROTATE` config and [auto_rotate](https://docs.imgproxy.net/generating_the_url?id=auto-rotate) processing option.
+- [rotate](https://docs.imgproxy.net/generating_the_url?id=rotate) processing option.
+- `width` and `height` arguments of the [crop](https://docs.imgproxy.net/generating_the_url?id=crop) processing option can be less than `1` that is treated by imgproxy as a relative value (a.k.a. crop by percentage).
 - (pro) Remove Adobe Illustrator garbage from SVGs.
 - (pro) Add IPTC tags to the `/info` response.
 
@@ -60,11 +68,11 @@
 
 ## [2.15.0] - 2020-09-03
 ### Added
-- Ability to skip processing of some formats. See [Skip processing](https://docs.imgproxy.net/#/configuration?id=skip-processing).
+- Ability to skip processing of some formats. See [Skip processing](https://docs.imgproxy.net/configuration?id=skip-processing).
 - (pro) PDF support.
-- (pro) [video_thumbnail_second](https://docs.imgproxy.net/#/generating_the_url?id=video-thumbnail-second) processing option.
-- (pro) [page](https://docs.imgproxy.net/#/generating_the_url?id=page) processing option.
-- (pro) [background_alpha](https://docs.imgproxy.net/#/generating_the_url?id=background-alpha) processing option.
+- (pro) [video_thumbnail_second](https://docs.imgproxy.net/generating_the_url?id=video-thumbnail-second) processing option.
+- (pro) [page](https://docs.imgproxy.net/generating_the_url?id=page) processing option.
+- (pro) [background_alpha](https://docs.imgproxy.net/generating_the_url?id=background-alpha) processing option.
 - (pro) `IMGPROXY_VIDEO_THUMBNAIL_PROBE_SIZE` and `IMGPROXY_VIDEO_THUMBNAIL_MAX_ANALYZE_DURATION` configs.
 
 ### Changed
@@ -82,8 +90,8 @@
 ## [2.14.0] - 2020-07-17
 ### Added
 - `IMGPROXY_PROMETHEUS_NAMESPACE` config.
-- [strip_metadata](https://docs.imgproxy.net/#/generating_the_url?id=strip-metadata) processing option.
-- (pro) Configurable unsharpening. See [Unsharpening](https://docs.imgproxy.net/#/configuration?id=unsharpening) configs and [unsharpening](https://docs.imgproxy.net/#/generating_the_url?id=unsharpening) processing option.
+- [strip_metadata](https://docs.imgproxy.net/generating_the_url?id=strip-metadata) processing option.
+- (pro) Configurable unsharpening. See [Unsharpening](https://docs.imgproxy.net/configuration?id=unsharpening) configs and [unsharpening](https://docs.imgproxy.net/generating_the_url?id=unsharpening) processing option.
 
 ### Changed
 - Better for libvips memory metrics for Prometheus.
@@ -105,7 +113,7 @@
 ## [2.13.0] - 2020-04-22
 ### Added
 - Fallback images.
-- [padding](https://docs.imgproxy.net/#/generating_the_url?id=padding) processing option.
+- [padding](https://docs.imgproxy.net/generating_the_url?id=padding) processing option.
 
 ### Changed
 - Optimized memory usage. Especially when dealing with animated images.
@@ -117,7 +125,7 @@
 ### Addded
 - `IMGPROXY_PATH_PREFIX` config.
 - (pro) Video thumbnails.
-- (pro) [Getting the image info](https://docs.imgproxy.net/#/getting_the_image_info).
+- (pro) [Getting the image info](https://docs.imgproxy.net/getting_the_image_info).
 
 ### Changed
 - Improved `trim` processing option.
diff --git a/docker/Dockerfile b/docker/Dockerfile
index 85d28049..34876f02 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -1,4 +1,4 @@
-ARG BASE_IMAGE_VERSION="v1.3.2"
+ARG BASE_IMAGE_VERSION="v1.4.0"
 
 FROM darthsim/imgproxy-base:${BASE_IMAGE_VERSION}
 LABEL maintainer="Sergey Alexandrovich <darthsim@gmail.com>"
@@ -9,7 +9,7 @@ RUN go build -v -o /usr/local/bin/imgproxy
 # ==================================================================================================
 # Final image
 
-FROM debian:buster-slim
+FROM debian:bullseye-slim
 LABEL maintainer="Sergey Alexandrovich <darthsim@gmail.com>"
 
 RUN apt-get update \
diff --git a/docs/generating_the_url.md b/docs/generating_the_url.md
index eb011139..eb65b79d 100644
--- a/docs/generating_the_url.md
+++ b/docs/generating_the_url.md
@@ -213,7 +213,9 @@ Removes surrounding background.
 
 **⚠️Warning:** Trimming requires an image to be fully loaded into memory. This disables scale-on-load and significantly increases memory usage and processing time. Use it carefully with large images.
 
-**📝Note:** If you know background color of your images then setting it explicitly via `color` will also save some resources because libvips won't detect it automatically.
+**📝Note:** If you know background color of your images then setting it explicitly via `color` will also save some resources because imgproxy won't detect it automatically.
+
+**📝Note:** Use `color` value of `FF00FF` for trimming transparent background as imgproxy uses magenta as a transparency key.
 
 **📝Note:** Trimming of animated images is not supported.
 
diff --git a/docs/index.html b/docs/index.html
index 028bc0bd..bd3def44 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -44,6 +44,12 @@
   <script src="assets/docsify-edit-link.js"></script>
   <script src="assets/docsify-gitter.js"></script>
   <script>
+    if (window.DOCSIFY_ROUTER_MODE === "history") {
+      var clink = document.createElement("link")
+      clink.rel = "canonical"
+      document.getElementsByTagName("head")[0].appendChild(clink)
+    }
+
     window.$docsify = {
       logo: '/assets/logo.svg',
       name: 'imgproxy',
@@ -51,13 +57,21 @@
       loadSidebar: true,
       subMaxLevel: 2,
       auto2top: true,
+      routerMode: window.DOCSIFY_ROUTER_MODE || "hash",
       search: {
         namespace: 'docs-imgproxy',
         depth: 6
       },
       plugins: [
         EditOnGithubPlugin.create('https://github.com/imgproxy/imgproxy/blob/master/docs/'),
-        GitterPlugin.create("imgproxy/imgproxy", "1775d3")
+        GitterPlugin.create("imgproxy/imgproxy", "1775d3"),
+        function (hook, vm) {
+          hook.beforeEach(function () {
+            if (clink) {
+              clink.href = "https://docs.imgproxy.net" + vm.route.path
+            }
+          });
+        }
       ]
     }
   </script>
diff --git a/netlify.toml b/netlify.toml
new file mode 100644
index 00000000..6f6a8518
--- /dev/null
+++ b/netlify.toml
@@ -0,0 +1,9 @@
+[build]
+  base="docs"
+  publish="/"
+  command=""
+
+[[redirects]]
+  from = "/*"
+  to = "/index.html"
+  status = 200
diff --git a/vips.c b/vips.c
index e7843bcb..0a472d4e 100644
--- a/vips.c
+++ b/vips.c
@@ -425,7 +425,7 @@ vips_trim(VipsImage *in, VipsImage **out, double threshold,
   VipsImage *tmp;
 
   if (vips_image_hasalpha(in)) {
-    if (vips_flatten(in, &tmp, NULL))
+    if (vips_flatten_go(in, &tmp, 255.0, 0, 255.0))
       return 1;
   } else {
     if (vips_copy(in, &tmp, NULL))