diff --git a/CHANGELOG.md b/CHANGELOG.md
index a8d909d..21bc4e6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,10 @@ Changelog](https://keepachangelog.com/en/1.0.0/), and this project adheres to
 
 ## [Unreleased]
 
+### Removed
+
+- Support for legacy course key building from object definition extensions [BC]
+
 ## [0.8.0] - 2023-06-19
 
 ### Changed
diff --git a/Dockerfile b/Dockerfile
index 71679cf..1a6e1b7 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,5 +1,5 @@
 # Install required libraries
-FROM golang:alpine AS builder
+FROM golang:alpine3.18 AS builder
 
 # Update installed packages
 RUN apk -U upgrade
diff --git a/src/dashboards/common.libsonnet b/src/dashboards/common.libsonnet
index 2552eb9..d243f73 100644
--- a/src/dashboards/common.libsonnet
+++ b/src/dashboards/common.libsonnet
@@ -8,9 +8,6 @@
   },
   fields: {
     actor_account_name: 'actor.account.name.keyword',
-    course: 'object.definition.extensions.http://adlnet.gov/expapi/activities/course.keyword',
-    school: 'object.definition.extensions.https://w3id.org/xapi/acrossx/extensions/school.keyword',
-    session: 'object.definition.extensions.http://adlnet.gov/expapi/activities/module.keyword',
     video_id: 'object.id.keyword',
     subtitle_enabled: 'context.extensions.https://w3id.org/xapi/video/extensions/cc-subtitle-enabled',
     full_screen: 'context.extensions.https://w3id.org/xapi/video/extensions/full-screen',
diff --git a/src/dashboards/teachers/common.libsonnet b/src/dashboards/teachers/common.libsonnet
index 5c65ae3..2c39444 100644
--- a/src/dashboards/teachers/common.libsonnet
+++ b/src/dashboards/teachers/common.libsonnet
@@ -37,9 +37,8 @@ local common = import '../common.libsonnet';
     course_title: 'SELECT `title` FROM courses_course WHERE `key`="${EDX_COURSE_KEY}"',
     course_start_date: 'SELECT DATE_FORMAT(start_date, "%d/%m/%Y") FROM courses_course WHERE `key`="${EDX_COURSE_KEY}"',
     course_end_date: 'SELECT DATE_FORMAT(end_date, "%d/%m/%Y") FROM courses_course WHERE `key`="${EDX_COURSE_KEY}"',
-    course_query: '%(course_key)s OR (%(school_course_session)s)' % {
+    course_query: '%(course_key)s' % {
       course_key: $.queries.course_key,
-      school_course_session: $.queries.school_course_session,
     },
     course_videos: 'object.id.keyword:${COURSE_VIDEOS_IDS_WITH_UUID:lucene}',
     downloads: '%(video_query)s AND verb.id:"%(verb_downloaded)s"' % {
@@ -47,11 +46,6 @@ local common = import '../common.libsonnet';
       verb_downloaded: common.verb_ids.downloaded,
     },
     edx_course_key: 'SELECT `key` FROM courses_course WHERE `key`="${EDX_COURSE_KEY}"',
-    school_course_session: '%(school)s:${SCHOOL:doublequote} AND %(course)s:${COURSE:doublequote} AND %(session)s:${SESSION:doublequote}' % {
-      course: common.utils.single_escape_string(common.fields.course),
-      school: common.utils.single_escape_string(common.fields.school),
-      session: common.utils.single_escape_string(common.fields.session),
-    },
     video_id: 'object.id.keyword:${VIDEO:doublequote}',
     views: '%(video_query)s AND verb.id:"%(verb_played)s" AND %(time)s:[0 TO %(view_count_threshold)s]' % {
       video_query: $.queries.video_id,
@@ -75,36 +69,6 @@ local common = import '../common.libsonnet';
       refresh='time',
       sort=1,
     ),
-    school: template.new(
-      name='SCHOOL',
-      current='all',
-      label='School',
-      datasource=common.datasources.edx_app,
-      query=$.queries.edx_course_key,
-      regex='/course-v1:(.*)\\+\\d+\\+.*/',
-      hide='variable',
-      refresh='time'
-    ),
-    course: template.new(
-      name='COURSE',
-      current='all',
-      label='Course',
-      datasource=common.datasources.edx_app,
-      query=$.queries.edx_course_key,
-      regex='/course-v1:.*\\+(\\d+)\\+.*/',
-      hide='variable',
-      refresh='time'
-    ),
-    session: template.new(
-      name='SESSION',
-      current='all',
-      label='Session',
-      datasource=common.datasources.edx_app,
-      query=$.queries.edx_course_key,
-      regex='/course-v1:.*\\+\\d+\\+(.*)/',
-      hide='variable',
-      refresh='time'
-    ),
     title: template.new(
       name='TITLE',
       current='all',
@@ -145,10 +109,9 @@ local common = import '../common.libsonnet';
       name='VIDEO',
       label='Video',
       datasource=common.datasources.lrs,
-      query='{"find": "terms", "field": "%(video_id)s", "query": "%(course_key)s OR (%(school_course_session)s)"}' % {
+      query='{"find": "terms", "field": "%(video_id)s", "query": "%(course_key)s"}' % {
         video_id: common.fields.video_id,
         course_key: $.queries.course_key,
-        school_course_session: std.strReplace($.queries.school_course_session, '\\', '\\\\'),
       },
       refresh='time'
     ),
@@ -158,10 +121,9 @@ local common = import '../common.libsonnet';
       hide='variable',
       label='Course videos identifiers',
       datasource=common.datasources.lrs,
-      query='{"find": "terms", "field": "%(video_id)s", "query": "%(course_key)s OR (%(school_course_session)s)"}' % {
+      query='{"find": "terms", "field": "%(video_id)s", "query": "%(course_key)s"}' % {
         video_id: common.fields.video_id,
         course_key: $.queries.course_key,
-        school_course_session: std.strReplace($.queries.school_course_session, '\\', '\\\\'),
       },
       multi='true',
       includeAll='true',
@@ -174,10 +136,9 @@ local common = import '../common.libsonnet';
       current='all',
       label='Video',
       datasource=common.datasources.lrs,
-      query='{"find": "terms", "field": "%(video_id)s", "query": "%(course_key)s OR (%(school_course_session)s)"}' % {
+      query='{"find": "terms", "field": "%(video_id)s", "query": "%(course_key)s"}' % {
         video_id: common.fields.video_id,
         course_key: $.queries.course_key,
-        school_course_session: std.strReplace($.queries.school_course_session, '\\', '\\\\'),
       },
       multi='true',
       includeAll='true',
diff --git a/src/dashboards/teachers/course.jsonnet b/src/dashboards/teachers/course.jsonnet
index 5bcaa1c..fb6fc68 100644
--- a/src/dashboards/teachers/course.jsonnet
+++ b/src/dashboards/teachers/course.jsonnet
@@ -20,9 +20,6 @@ dashboard.new(
 )
 .addLink(teachers_common.link.teacher)
 .addTemplate(teachers_common.templates.edx_course_key)
-.addTemplate(teachers_common.templates.school)
-.addTemplate(teachers_common.templates.course)
-.addTemplate(teachers_common.templates.session)
 .addTemplate(teachers_common.templates.title)
 .addTemplate(teachers_common.templates.start_date)
 .addTemplate(teachers_common.templates.end_date)
diff --git a/src/dashboards/teachers/details.jsonnet b/src/dashboards/teachers/details.jsonnet
index 8a76d37..e7bb528 100644
--- a/src/dashboards/teachers/details.jsonnet
+++ b/src/dashboards/teachers/details.jsonnet
@@ -18,9 +18,6 @@ dashboard.new(
 )
 .addLink(teachers_common.link.teacher)
 .addTemplate(teachers_common.templates.edx_course_key)
-.addTemplate(teachers_common.templates.school)
-.addTemplate(teachers_common.templates.course)
-.addTemplate(teachers_common.templates.session)
 .addTemplate(teachers_common.templates.video)
 .addPanel(
   row.new(title='Views metrics', collapse=false),
@@ -237,7 +234,7 @@ dashboard.new(
       A view is counted when the user has clicked the play button in the interface
       in the first %(view_count_threshold)s seconds of the video.
 
-      A complete view is counted when the user has viewed the video 
+      A complete view is counted when the user has viewed the video
       at least up to the completion threshold.
 
       A download is counted when the user downloads the video files from Marsha.