diff --git a/docs/docs/guides/server-deployment.md b/docs/docs/guides/server-deployment.md
index fb50f5592b..f1d7546d77 100644
--- a/docs/docs/guides/server-deployment.md
+++ b/docs/docs/guides/server-deployment.md
@@ -228,7 +228,7 @@ When using  [files](../concepts/dev-environments.md#files) or [repos](../concept
 
 ### S3
 
-To use S3 for storing uploaded files, set the `DSTACK_SERVER_S3_BUCKET` and `DSTACK_SERVER_BUCKET_REGION` environment variables.
+To use S3 for storing uploaded files, set the `DSTACK_SERVER_S3_BUCKET` and `DSTACK_SERVER_S3_BUCKET_REGION` environment variables.
 The bucket must be created beforehand. `dstack` won't try to create it.
 
 ??? info "Required permissions"
diff --git a/src/dstack/_internal/cli/commands/offer.py b/src/dstack/_internal/cli/commands/offer.py
index 33f3656d02..bc6bb0a5db 100644
--- a/src/dstack/_internal/cli/commands/offer.py
+++ b/src/dstack/_internal/cli/commands/offer.py
@@ -105,7 +105,6 @@ def _command(self, args: argparse.Namespace):
         run_spec = RunSpec(
             configuration=conf,
             profile=profile,
-            ssh_key_pub="(dummy)",  # TODO: Remove since 0.19.40
         )
 
         if args.group_by:
diff --git a/src/dstack/_internal/cli/services/configurators/fleet.py b/src/dstack/_internal/cli/services/configurators/fleet.py
index 36eaaf8fe7..89278feb94 100644
--- a/src/dstack/_internal/cli/services/configurators/fleet.py
+++ b/src/dstack/_internal/cli/services/configurators/fleet.py
@@ -20,10 +20,8 @@
 from dstack._internal.core.errors import (
     CLIError,
     ConfigurationError,
-    MethodNotAllowedError,
     ResourceNotExistsError,
     ServerClientError,
-    URLNotFoundError,
 )
 from dstack._internal.core.models.common import ApplyAction
 from dstack._internal.core.models.configurations import ApplyConfigurationType
@@ -39,7 +37,6 @@
 from dstack._internal.utils.common import local_time
 from dstack._internal.utils.logging import get_logger
 from dstack._internal.utils.ssh import convert_ssh_key_to_pem, generate_public_key, pkey_from_str
-from dstack.api._public import Client
 from dstack.api.utils import load_profile
 
 logger = get_logger(__name__)
@@ -233,7 +230,7 @@ def _apply_plan_on_old_server(self, plan: FleetPlan, command_args: argparse.Name
 
         try:
             with console.status("Applying plan..."):
-                fleet = _apply_plan(self.api, plan)
+                fleet = self.api.client.fleets.apply_plan(project_name=self.api.project, plan=plan)
         except ServerClientError as e:
             raise CLIError(e.msg)
         if command_args.detach:
@@ -481,17 +478,3 @@ def _fleet_retrying(fleet: Fleet) -> bool:
         return False
     active_instances = [i for i in fleet.instances if i.status.is_active()]
     return len(active_instances) < fleet.spec.configuration.nodes.min
-
-
-def _apply_plan(api: Client, plan: FleetPlan) -> Fleet:
-    try:
-        return api.client.fleets.apply_plan(
-            project_name=api.project,
-            plan=plan,
-        )
-    except (URLNotFoundError, MethodNotAllowedError):
-        # TODO: Remove in 0.20
-        return api.client.fleets.create(
-            project_name=api.project,
-            spec=plan.spec,
-        )
diff --git a/src/dstack/_internal/core/backends/azure/compute.py b/src/dstack/_internal/core/backends/azure/compute.py
index 8573ec99ab..0089f5e478 100644
--- a/src/dstack/_internal/core/backends/azure/compute.py
+++ b/src/dstack/_internal/core/backends/azure/compute.py
@@ -420,11 +420,6 @@ def get_image_name(self) -> str:
     r"NC(\d+)ads_A100_v4",  # NC A100 v4-series [A100 80GB]
     r"ND(\d+)asr_v4",  # ND A100 v4-series [8xA100 40GB]
     r"ND(\d+)amsr_A100_v4",  # NDm A100 v4-series [8xA100 80GB]
-    # Deprecated series
-    # TODO: Remove after several releases
-    r"D(\d+)s_v3",  # Dsv3-series (general purpose)
-    r"E(\d+)i?s_v4",  # Esv4-series (memory optimized)
-    r"E(\d+)-(\d+)s_v4",  # Esv4-series (constrained vCPU)
 ]
 _SUPPORTED_VM_SERIES_PATTERN = (
     "^Standard_(" + "|".join(f"({s})" for s in _SUPPORTED_VM_SERIES_PATTERNS) + ")$"
diff --git a/src/dstack/_internal/core/backends/kubernetes/compute.py b/src/dstack/_internal/core/backends/kubernetes/compute.py
index 71a59ad225..da5e125b96 100644
--- a/src/dstack/_internal/core/backends/kubernetes/compute.py
+++ b/src/dstack/_internal/core/backends/kubernetes/compute.py
@@ -34,8 +34,6 @@
 from dstack._internal.core.consts import DSTACK_RUNNER_SSH_PORT
 from dstack._internal.core.errors import ComputeError
 from dstack._internal.core.models.backends.base import BackendType
-
-# TODO: update import as KNOWN_GPUS becomes public
 from dstack._internal.core.models.gateways import (
     GatewayComputeConfiguration,
     GatewayProvisioningData,
diff --git a/src/dstack/_internal/core/compatibility/fleets.py b/src/dstack/_internal/core/compatibility/fleets.py
index 2ac640b27f..e22903df34 100644
--- a/src/dstack/_internal/core/compatibility/fleets.py
+++ b/src/dstack/_internal/core/compatibility/fleets.py
@@ -2,7 +2,6 @@
 
 from dstack._internal.core.models.common import IncludeExcludeDictType, IncludeExcludeSetType
 from dstack._internal.core.models.fleets import ApplyFleetPlanInput, FleetSpec
-from dstack._internal.core.models.instances import Instance
 
 
 def get_get_plan_excludes(fleet_spec: FleetSpec) -> IncludeExcludeDictType:
@@ -22,10 +21,6 @@ def get_apply_plan_excludes(plan_input: ApplyFleetPlanInput) -> IncludeExcludeDi
     if current_resource is not None:
         current_resource_excludes = {}
         apply_plan_excludes["current_resource"] = current_resource_excludes
-        if all(map(_should_exclude_instance_cpu_arch, current_resource.instances)):
-            current_resource_excludes["instances"] = {
-                "__all__": {"instance_type": {"resources": {"cpu_arch"}}}
-            }
     return {"plan": apply_plan_excludes}
 
 
@@ -46,24 +41,14 @@ def get_fleet_spec_excludes(fleet_spec: FleetSpec) -> Optional[IncludeExcludeDic
     spec_excludes: IncludeExcludeDictType = {}
     configuration_excludes: IncludeExcludeDictType = {}
     profile_excludes: IncludeExcludeSetType = set()
-    profile = fleet_spec.profile
-    if profile.fleets is None:
-        profile_excludes.add("fleets")
-    if fleet_spec.configuration.tags is None:
-        configuration_excludes["tags"] = True
-    if profile.tags is None:
-        profile_excludes.add("tags")
-    if profile.startup_order is None:
-        profile_excludes.add("startup_order")
-    if profile.stop_criteria is None:
-        profile_excludes.add("stop_criteria")
-    if profile.schedule is None:
-        profile_excludes.add("schedule")
-    if (
-        fleet_spec.configuration.nodes
-        and fleet_spec.configuration.nodes.min == fleet_spec.configuration.nodes.target
-    ):
-        configuration_excludes["nodes"] = {"target"}
+
+    # Add excludes like this:
+    #
+    # if fleet_spec.configuration.tags is None:
+    #     configuration_excludes["tags"] = True
+    # if fleet_spec.profile.tags is None:
+    #     profile_excludes.add("tags")
+
     if configuration_excludes:
         spec_excludes["configuration"] = configuration_excludes
     if profile_excludes:
@@ -71,10 +56,3 @@ def get_fleet_spec_excludes(fleet_spec: FleetSpec) -> Optional[IncludeExcludeDic
     if spec_excludes:
         return spec_excludes
     return None
-
-
-def _should_exclude_instance_cpu_arch(instance: Instance) -> bool:
-    try:
-        return instance.instance_type.resources.cpu_arch is None
-    except AttributeError:
-        return True
diff --git a/src/dstack/_internal/core/compatibility/gateways.py b/src/dstack/_internal/core/compatibility/gateways.py
index 2b9ed18dd9..de94f6a18e 100644
--- a/src/dstack/_internal/core/compatibility/gateways.py
+++ b/src/dstack/_internal/core/compatibility/gateways.py
@@ -30,8 +30,10 @@ def _get_gateway_configuration_excludes(
     configuration: GatewayConfiguration,
 ) -> IncludeExcludeDictType:
     configuration_excludes: IncludeExcludeDictType = {}
-    if configuration.tags is None:
-        configuration_excludes["tags"] = True
-    if configuration.router is None:
-        configuration_excludes["router"] = True
+
+    # Add excludes like this:
+    #
+    # if configuration.tags is None:
+    #     configuration_excludes["tags"] = True
+
     return configuration_excludes
diff --git a/src/dstack/_internal/core/compatibility/logs.py b/src/dstack/_internal/core/compatibility/logs.py
index 7d499047ae..078ce62218 100644
--- a/src/dstack/_internal/core/compatibility/logs.py
+++ b/src/dstack/_internal/core/compatibility/logs.py
@@ -11,6 +11,4 @@ def get_poll_logs_excludes(request: PollLogsRequest) -> Optional[IncludeExcludeD
     clients backward-compatibility with older servers.
     """
     excludes: IncludeExcludeDictType = {}
-    if request.next_token is None:
-        excludes["next_token"] = True
     return excludes if excludes else None
diff --git a/src/dstack/_internal/core/compatibility/runs.py b/src/dstack/_internal/core/compatibility/runs.py
index 0cf9cfb9e2..5bec348d67 100644
--- a/src/dstack/_internal/core/compatibility/runs.py
+++ b/src/dstack/_internal/core/compatibility/runs.py
@@ -1,18 +1,12 @@
 from typing import Optional
 
 from dstack._internal.core.models.common import IncludeExcludeDictType, IncludeExcludeSetType
-from dstack._internal.core.models.configurations import LEGACY_REPO_DIR, ServiceConfiguration
-from dstack._internal.core.models.runs import ApplyRunPlanInput, JobSpec, JobSubmission, RunSpec
+from dstack._internal.core.models.runs import ApplyRunPlanInput, JobSpec, RunSpec
 from dstack._internal.server.schemas.runs import GetRunPlanRequest, ListRunsRequest
-from dstack._internal.settings import FeatureFlags
 
 
 def get_list_runs_excludes(list_runs_request: ListRunsRequest) -> IncludeExcludeSetType:
-    excludes = set()
-    if list_runs_request.include_jobs:
-        excludes.add("include_jobs")
-    if list_runs_request.job_submissions_limit is None:
-        excludes.add("job_submissions_limit")
+    excludes: IncludeExcludeSetType = set()
     return excludes
 
 
@@ -29,82 +23,7 @@ def get_apply_plan_excludes(plan: ApplyRunPlanInput) -> Optional[IncludeExcludeD
     current_resource = plan.current_resource
     if current_resource is not None:
         current_resource_excludes: IncludeExcludeDictType = {}
-        current_resource_excludes["status_message"] = True
-        if current_resource.deployment_num == 0:
-            current_resource_excludes["deployment_num"] = True
-        if current_resource.fleet is None:
-            current_resource_excludes["fleet"] = True
-        if current_resource.next_triggered_at is None:
-            current_resource_excludes["next_triggered_at"] = True
-        apply_plan_excludes["current_resource"] = current_resource_excludes
         current_resource_excludes["run_spec"] = get_run_spec_excludes(current_resource.run_spec)
-        job_submissions_excludes: IncludeExcludeDictType = {}
-        current_resource_excludes["jobs"] = {
-            "__all__": {
-                "job_spec": get_job_spec_excludes([job.job_spec for job in current_resource.jobs]),
-                "job_submissions": {"__all__": job_submissions_excludes},
-            }
-        }
-        job_submissions = [js for j in current_resource.jobs for js in j.job_submissions]
-        if all(map(_should_exclude_job_submission_jpd_cpu_arch, job_submissions)):
-            job_submissions_excludes["job_provisioning_data"] = {
-                "instance_type": {"resources": {"cpu_arch"}}
-            }
-        jrd_offer_excludes = {}
-        if any(
-            js.job_runtime_data and js.job_runtime_data.offer for js in job_submissions
-        ) and all(
-            not js.job_runtime_data
-            or not js.job_runtime_data.offer
-            or not js.job_runtime_data.offer.backend_data
-            for js in job_submissions
-        ):
-            jrd_offer_excludes["backend_data"] = True
-        if all(map(_should_exclude_job_submission_jrd_cpu_arch, job_submissions)):
-            jrd_offer_excludes["instance"] = {"resources": {"cpu_arch"}}
-        if jrd_offer_excludes:
-            job_submissions_excludes["job_runtime_data"] = {"offer": jrd_offer_excludes}
-        if all(js.exit_status is None for js in job_submissions):
-            job_submissions_excludes["exit_status"] = True
-        if all(js.status_message == "" for js in job_submissions):
-            job_submissions_excludes["status_message"] = True
-        if all(js.error is None for js in job_submissions):
-            job_submissions_excludes["error"] = True
-        if all(js.deployment_num == 0 for js in job_submissions):
-            job_submissions_excludes["deployment_num"] = True
-        if all(not js.probes for js in job_submissions):
-            job_submissions_excludes["probes"] = True
-        latest_job_submission = current_resource.latest_job_submission
-        if latest_job_submission is not None:
-            latest_job_submission_excludes: IncludeExcludeDictType = {}
-            current_resource_excludes["latest_job_submission"] = latest_job_submission_excludes
-            if _should_exclude_job_submission_jpd_cpu_arch(latest_job_submission):
-                latest_job_submission_excludes["job_provisioning_data"] = {
-                    "instance_type": {"resources": {"cpu_arch"}}
-                }
-            latest_job_submission_jrd_offer_excludes = {}
-            if (
-                latest_job_submission.job_runtime_data
-                and latest_job_submission.job_runtime_data.offer
-                and not latest_job_submission.job_runtime_data.offer.backend_data
-            ):
-                latest_job_submission_jrd_offer_excludes["backend_data"] = True
-            if _should_exclude_job_submission_jrd_cpu_arch(latest_job_submission):
-                latest_job_submission_jrd_offer_excludes["instance"] = {"resources": {"cpu_arch"}}
-            if latest_job_submission_jrd_offer_excludes:
-                latest_job_submission_excludes["job_runtime_data"] = {
-                    "offer": latest_job_submission_jrd_offer_excludes
-                }
-            if latest_job_submission.exit_status is None:
-                latest_job_submission_excludes["exit_status"] = True
-            if latest_job_submission.status_message == "":
-                latest_job_submission_excludes["status_message"] = True
-            if latest_job_submission.error is None:
-                latest_job_submission_excludes["error"] = True
-            if latest_job_submission.deployment_num == 0:
-                latest_job_submission_excludes["deployment_num"] = True
-            if not latest_job_submission.probes:
-                latest_job_submission_excludes["probes"] = True
     return {"plan": apply_plan_excludes}
 
 
@@ -117,8 +36,6 @@ def get_get_plan_excludes(request: GetRunPlanRequest) -> Optional[IncludeExclude
     run_spec_excludes = get_run_spec_excludes(request.run_spec)
     if run_spec_excludes is not None:
         get_plan_excludes["run_spec"] = run_spec_excludes
-    if request.max_offers is None:
-        get_plan_excludes["max_offers"] = True
     return get_plan_excludes
 
 
@@ -131,53 +48,13 @@ def get_run_spec_excludes(run_spec: RunSpec) -> IncludeExcludeDictType:
     spec_excludes: IncludeExcludeDictType = {}
     configuration_excludes: IncludeExcludeDictType = {}
     profile_excludes: IncludeExcludeSetType = set()
-    configuration = run_spec.configuration
-    profile = run_spec.profile
 
-    if not FeatureFlags.LEGACY_REPO_DIR_DISABLED:
-        if run_spec.repo_dir in [None, LEGACY_REPO_DIR]:
-            spec_excludes["repo_dir"] = True
-        elif run_spec.repo_dir == "." and configuration.working_dir in [
-            None,
-            LEGACY_REPO_DIR,
-            ".",
-        ]:
-            spec_excludes["repo_dir"] = True
-
-    if configuration.fleets is None:
-        configuration_excludes["fleets"] = True
-    if profile is not None and profile.fleets is None:
-        profile_excludes.add("fleets")
-    if configuration.tags is None:
-        configuration_excludes["tags"] = True
-    if profile is not None and profile.tags is None:
-        profile_excludes.add("tags")
-    if isinstance(configuration, ServiceConfiguration) and not configuration.rate_limits:
-        configuration_excludes["rate_limits"] = True
-    if configuration.shell is None:
-        configuration_excludes["shell"] = True
-    if configuration.docker is None:
-        configuration_excludes["docker"] = True
-    if configuration.priority is None:
-        configuration_excludes["priority"] = True
-    if configuration.startup_order is None:
-        configuration_excludes["startup_order"] = True
-    if profile is not None and profile.startup_order is None:
-        profile_excludes.add("startup_order")
-    if configuration.stop_criteria is None:
-        configuration_excludes["stop_criteria"] = True
-    if isinstance(configuration, ServiceConfiguration) and not configuration.probes:
-        configuration_excludes["probes"] = True
-    if profile is not None and profile.stop_criteria is None:
-        profile_excludes.add("stop_criteria")
-    if not configuration.files:
-        configuration_excludes["files"] = True
-    if not run_spec.file_archives:
-        spec_excludes["file_archives"] = True
-    if configuration.schedule is None:
-        configuration_excludes["schedule"] = True
-    if profile is not None and profile.schedule is None:
-        profile_excludes.add("schedule")
+    # Add excludes like this:
+    #
+    # if run_spec.configuration.tags is None:
+    #     configuration_excludes["tags"] = True
+    # if run_spec.profile is not None and run_spec.profile.tags is None:
+    #     profile_excludes.add("tags")
 
     if configuration_excludes:
         spec_excludes["configuration"] = configuration_excludes
@@ -193,34 +70,4 @@ def get_job_spec_excludes(job_specs: list[JobSpec]) -> IncludeExcludeDictType:
     clients backward-compatibility with older servers.
     """
     spec_excludes: IncludeExcludeDictType = {}
-
-    if all(s.repo_code_hash is None for s in job_specs):
-        spec_excludes["repo_code_hash"] = True
-    if all(s.repo_data is None for s in job_specs):
-        spec_excludes["repo_data"] = True
-    if all(not s.file_archives for s in job_specs):
-        spec_excludes["file_archives"] = True
-    if all(s.service_port is None for s in job_specs):
-        spec_excludes["service_port"] = True
-    if all(not s.probes for s in job_specs):
-        spec_excludes["probes"] = True
-    if all(s.repo_dir in [None, LEGACY_REPO_DIR] for s in job_specs):
-        spec_excludes["repo_dir"] = True
-    if all(s.requirements.multinode is None for s in job_specs):
-        spec_excludes["requirements"] = {"multinode": True}
-
     return spec_excludes
-
-
-def _should_exclude_job_submission_jpd_cpu_arch(job_submission: JobSubmission) -> bool:
-    try:
-        return job_submission.job_provisioning_data.instance_type.resources.cpu_arch is None
-    except AttributeError:
-        return True
-
-
-def _should_exclude_job_submission_jrd_cpu_arch(job_submission: JobSubmission) -> bool:
-    try:
-        return job_submission.job_runtime_data.offer.instance.resources.cpu_arch is None
-    except AttributeError:
-        return True
diff --git a/src/dstack/_internal/core/compatibility/volumes.py b/src/dstack/_internal/core/compatibility/volumes.py
index 4b7be6bb00..191005e130 100644
--- a/src/dstack/_internal/core/compatibility/volumes.py
+++ b/src/dstack/_internal/core/compatibility/volumes.py
@@ -28,8 +28,10 @@ def _get_volume_configuration_excludes(
     configuration: VolumeConfiguration,
 ) -> IncludeExcludeDictType:
     configuration_excludes: IncludeExcludeDictType = {}
-    if configuration.tags is None:
-        configuration_excludes["tags"] = True
-    if configuration.auto_cleanup_duration is None:
-        configuration_excludes["auto_cleanup_duration"] = True
+
+    # Add excludes like this:
+    #
+    # if configuration.tags is None:
+    #     configuration_excludes["tags"] = True
+
     return configuration_excludes
diff --git a/src/dstack/_internal/core/models/fleets.py b/src/dstack/_internal/core/models/fleets.py
index 1137c38dba..c88f606640 100644
--- a/src/dstack/_internal/core/models/fleets.py
+++ b/src/dstack/_internal/core/models/fleets.py
@@ -21,7 +21,6 @@
     ProfileParams,
     ProfileRetry,
     SpotPolicy,
-    TerminationPolicy,
     parse_idle_duration,
 )
 from dstack._internal.core.models.resources import ResourcesSpec
@@ -210,8 +209,6 @@ def _post_validate_ranges(cls, values):
 class InstanceGroupParamsConfig(CoreConfig):
     @staticmethod
     def schema_extra(schema: Dict[str, Any]):
-        del schema["properties"]["termination_policy"]
-        del schema["properties"]["termination_idle_time"]
         add_extra_schema_types(
             schema["properties"]["nodes"],
             extra_types=[{"type": "integer"}, {"type": "string"}],
@@ -318,10 +315,6 @@ class InstanceGroupParams(CoreModel):
         ),
     ] = None
 
-    # Deprecated and unused. Left for compatibility with 0.18 clients.
-    termination_policy: Annotated[Optional[TerminationPolicy], Field(exclude=True)] = None
-    termination_idle_time: Annotated[Optional[Union[str, int]], Field(exclude=True)] = None
-
     @validator("nodes", pre=True)
     def parse_nodes(cls, v: Optional[Union[dict, str]]) -> Optional[dict]:
         if isinstance(v, str) and ".." in v:
diff --git a/src/dstack/_internal/core/models/gateways.py b/src/dstack/_internal/core/models/gateways.py
index 39befe7392..ace68e5429 100644
--- a/src/dstack/_internal/core/models/gateways.py
+++ b/src/dstack/_internal/core/models/gateways.py
@@ -96,10 +96,11 @@ class Gateway(CoreModel):
     instance_id: Optional[str]
     wildcard_domain: Optional[str]
     default: bool
-    # TODO: configuration fields are duplicated on top-level for backward compatibility with 0.18.x
-    # Remove after 0.19
-    backend: BackendType
-    region: str
+    # TODO: Deprecated configuration fields duplicated on top-level
+    # for backward compatibility with 0.19.x clients that expect them required.
+    # Remove after 0.21
+    backend: Optional[BackendType] = None
+    region: Optional[str] = None
 
 
 class GatewayPlan(CoreModel):
diff --git a/src/dstack/_internal/core/models/profiles.py b/src/dstack/_internal/core/models/profiles.py
index 7fae65e762..896049ffa6 100644
--- a/src/dstack/_internal/core/models/profiles.py
+++ b/src/dstack/_internal/core/models/profiles.py
@@ -242,11 +242,6 @@ def crons(self) -> List[str]:
 class ProfileParamsConfig(CoreConfig):
     @staticmethod
     def schema_extra(schema: Dict[str, Any]):
-        del schema["properties"]["pool_name"]
-        del schema["properties"]["instance_name"]
-        del schema["properties"]["retry_policy"]
-        del schema["properties"]["termination_policy"]
-        del schema["properties"]["termination_idle_time"]
         add_extra_schema_types(
             schema["properties"]["max_duration"],
             extra_types=[{"type": "boolean"}, {"type": "string"}],
@@ -396,13 +391,6 @@ class ProfileParams(CoreModel):
         ),
     ] = None
 
-    # Deprecated and unused. Left for compatibility with 0.18 clients.
-    pool_name: Annotated[Optional[str], Field(exclude=True)] = None
-    instance_name: Annotated[Optional[str], Field(exclude=True)] = None
-    retry_policy: Annotated[Optional[ProfileRetryPolicy], Field(exclude=True)] = None
-    termination_policy: Annotated[Optional[TerminationPolicy], Field(exclude=True)] = None
-    termination_idle_time: Annotated[Optional[Union[str, int]], Field(exclude=True)] = None
-
     _validate_max_duration = validator("max_duration", pre=True, allow_reuse=True)(
         parse_max_duration
     )
diff --git a/src/dstack/_internal/core/models/repos/remote.py b/src/dstack/_internal/core/models/repos/remote.py
index 8d6d371952..fedadee0ff 100644
--- a/src/dstack/_internal/core/models/repos/remote.py
+++ b/src/dstack/_internal/core/models/repos/remote.py
@@ -3,7 +3,7 @@
 import subprocess
 import time
 from dataclasses import dataclass
-from typing import Annotated, Any, BinaryIO, Callable, Dict, Optional
+from typing import Any, BinaryIO, Callable, Dict, Optional
 
 import git
 import pydantic
@@ -27,7 +27,7 @@ class RepoError(DstackError):
 class RemoteRepoCredsConfig(CoreConfig):
     @staticmethod
     def schema_extra(schema: Dict[str, Any]):
-        del schema["properties"]["protocol"]
+        pass
 
 
 class RemoteRepoCreds(generate_dual_core_model(RemoteRepoCredsConfig)):
@@ -35,16 +35,11 @@ class RemoteRepoCreds(generate_dual_core_model(RemoteRepoCredsConfig)):
     private_key: Optional[str] = None
     oauth_token: Optional[str] = None
 
-    # TODO: remove in 0.20. Left for compatibility with CLI <=0.18.44
-    protocol: Annotated[Optional[str], Field(exclude=True)] = None
-
 
 class RemoteRepoInfoConfig(CoreConfig):
     @staticmethod
     def schema_extra(schema: Dict[str, Any]):
-        del schema["properties"]["repo_host_name"]
-        del schema["properties"]["repo_port"]
-        del schema["properties"]["repo_user_name"]
+        pass
 
 
 class RemoteRepoInfo(
@@ -54,11 +49,6 @@ class RemoteRepoInfo(
     repo_type: Literal["remote"] = "remote"
     repo_name: str
 
-    # TODO: remove in 0.20. Left for compatibility with CLI <=0.18.44
-    repo_host_name: Annotated[Optional[str], Field(exclude=True)] = None
-    repo_port: Annotated[Optional[int], Field(exclude=True)] = None
-    repo_user_name: Annotated[Optional[str], Field(exclude=True)] = None
-
 
 class RemoteRunRepoData(RemoteRepoInfo):
     repo_branch: Optional[str] = None
diff --git a/src/dstack/_internal/core/models/runs.py b/src/dstack/_internal/core/models/runs.py
index ec657e7987..841d58bd66 100644
--- a/src/dstack/_internal/core/models/runs.py
+++ b/src/dstack/_internal/core/models/runs.py
@@ -203,7 +203,6 @@ def to_error(self) -> Optional[str]:
 
 
 class Requirements(CoreModel):
-    # TODO: Make requirements' fields required
     resources: ResourcesSpec
     max_price: Optional[float] = None
     spot: Optional[bool] = None
diff --git a/src/dstack/_internal/server/background/tasks/process_running_jobs.py b/src/dstack/_internal/server/background/tasks/process_running_jobs.py
index 72c5417c12..ba2d96a135 100644
--- a/src/dstack/_internal/server/background/tasks/process_running_jobs.py
+++ b/src/dstack/_internal/server/background/tasks/process_running_jobs.py
@@ -386,8 +386,7 @@ async def _process_running_job(session: AsyncSession, job_model: JobModel):
                         fmt(job_model),
                         job_submission.age,
                     )
-                    # TODO: Replace with JobTerminationReason.INSTANCE_UNREACHABLE in 0.20 or
-                    # when CLI <= 0.19.8 is no longer supported
+                    # TODO: Replace with JobTerminationReason.INSTANCE_UNREACHABLE for on-demand.
                     job_model.termination_reason = JobTerminationReason.INTERRUPTED_BY_NO_CAPACITY
                     job_model.status = JobStatus.TERMINATING
                 else:
diff --git a/src/dstack/_internal/server/models.py b/src/dstack/_internal/server/models.py
index 04185762a1..374b359edb 100644
--- a/src/dstack/_internal/server/models.py
+++ b/src/dstack/_internal/server/models.py
@@ -637,7 +637,7 @@ class InstanceModel(BaseModel):
     termination_deadline: Mapped[Optional[datetime]] = mapped_column(NaiveDateTime)
     termination_reason: Mapped[Optional[str]] = mapped_column(String(4000))
     # Deprecated since 0.19.22, not used
-    health_status: Mapped[Optional[str]] = mapped_column(String(4000))
+    health_status: Mapped[Optional[str]] = mapped_column(String(4000), deferred=True)
     health: Mapped[HealthStatus] = mapped_column(
         EnumAsString(HealthStatus, 100), default=HealthStatus.HEALTHY
     )
diff --git a/src/dstack/_internal/server/routers/fleets.py b/src/dstack/_internal/server/routers/fleets.py
index 3cbab9508c..7e7126f4bf 100644
--- a/src/dstack/_internal/server/routers/fleets.py
+++ b/src/dstack/_internal/server/routers/fleets.py
@@ -138,7 +138,7 @@ async def apply_plan(
     )
 
 
-@project_router.post("/create", response_model=Fleet)
+@project_router.post("/create", response_model=Fleet, deprecated=True)
 async def create_fleet(
     body: CreateFleetRequest,
     session: AsyncSession = Depends(get_session),
diff --git a/src/dstack/_internal/server/schemas/gateways.py b/src/dstack/_internal/server/schemas/gateways.py
index ffad6e78ab..9c00caa2e3 100644
--- a/src/dstack/_internal/server/schemas/gateways.py
+++ b/src/dstack/_internal/server/schemas/gateways.py
@@ -1,8 +1,5 @@
-from typing import Annotated, Any, Dict, List, Optional
+from typing import Any, Dict, List
 
-from pydantic import Field
-
-from dstack._internal.core.models.backends.base import BackendType
 from dstack._internal.core.models.common import CoreConfig, CoreModel, generate_dual_core_model
 from dstack._internal.core.models.gateways import GatewayConfiguration
 
@@ -10,17 +7,11 @@
 class CreateGatewayRequestConfig(CoreConfig):
     @staticmethod
     def schema_extra(schema: Dict[str, Any]):
-        del schema["properties"]["name"]
-        del schema["properties"]["backend_type"]
-        del schema["properties"]["region"]
+        pass
 
 
 class CreateGatewayRequest(generate_dual_core_model(CreateGatewayRequestConfig)):
     configuration: GatewayConfiguration
-    # Deprecated and unused. Left for compatibility with 0.18 clients.
-    name: Annotated[Optional[str], Field(exclude=True)] = None
-    backend_type: Annotated[Optional[BackendType], Field(exclude=True)] = None
-    region: Annotated[Optional[str], Field(exclude=True)] = None
 
 
 class GetGatewayRequest(CoreModel):
diff --git a/src/dstack/api/_public/runs.py b/src/dstack/api/_public/runs.py
index f7d3a0170d..6a4843b023 100644
--- a/src/dstack/api/_public/runs.py
+++ b/src/dstack/api/_public/runs.py
@@ -825,7 +825,7 @@ def list(self, all: bool = False, limit: Optional[int] = None) -> List[Run]:
             repo_id=None,
             only_active=only_active,
             limit=limit or 100,
-            # TODO: Pass job_submissions_limit=1 in 0.20
+            job_submissions_limit=1,
         )
         if only_active and len(runs) == 0:
             runs = self._api_client.runs.list(
diff --git a/src/dstack/api/server/_fleets.py b/src/dstack/api/server/_fleets.py
index 942f12c27a..8f6ea7fcfa 100644
--- a/src/dstack/api/server/_fleets.py
+++ b/src/dstack/api/server/_fleets.py
@@ -63,7 +63,7 @@ def delete_instances(self, project_name: str, name: str, instance_nums: List[int
         self._request(f"/api/project/{project_name}/fleets/delete_instances", body=body.json())
 
     # Deprecated
-    # TODO: Remove in 0.20
+    # TODO: Remove in 0.21
     def create(
         self,
         project_name: str,
diff --git a/src/tests/_internal/server/background/tasks/test_process_runs.py b/src/tests/_internal/server/background/tasks/test_process_runs.py
index ca1ac060ef..81c1ef0026 100644
--- a/src/tests/_internal/server/background/tasks/test_process_runs.py
+++ b/src/tests/_internal/server/background/tasks/test_process_runs.py
@@ -1015,7 +1015,3 @@ async def test_stops_unregistered_out_of_date_replicas_unconditionally(
             cast(JobSpec, JobSpec.__response__.parse_raw(run.jobs[2].job_spec_data)).image_name
             == "new"
         )
-
-
-# TODO(egor-s): TestProcessRunsMultiNode
-# TODO(egor-s): TestProcessRunsAutoScaling